Tech Tips

Have a tech question? Ask Dave

The following articles are based on Dave's many years of experience working with boats and motors of all shapes and sizes. Many of these tips are compilations of his postings in the rec.boating newsgroup. Please remember, that if someone doesn't understand something drop Dave a line or ask your local professional. There are professionals out there who know what they're doing and will properly care for your boat.

But for the do-it-yourselfer (or those that want to make sure their local professional really knows what they are doing), here are some tips:

  • Reformulated gasoline


    Even though this article was written over 20 years ago, it's content remains unchanged except that government regulations have allowed (in some cases mandated) reformulated fuels contain up to 15% alcohol and that has resulted in a huge increase in service issues directly related to these fuels. In short, older fuel systems were never designed for this level of concentration, and water saturation of these fuels has become an ongoing issue in our service schedule. Read the following article if you have time, if you don't, use only PREMIUM fuel in your boat (as most do not contain alcohols) and keep your tank FULL during the offseason. Do NOT be sucked into thinking a "snake oil" additive will magically convert your ethanol laced fuel into something your engine won't mind - it cannot and does not!

    Three things to remember about alcohol:

    First, it attracts and holds moisture. This can cause corrosion in fuel system (which is a fire hazzard) and cause your engine to misfire or not run at all.

    Next, it's a solvent, so it attacks rubber fuel and gasket components which can cause leaks and is therefore a fire hazzard, and of course cause engine running issues.

    Lastly, it's unstable and has a short shelf life (usually no more than 90days)

    Read on for the full scoop:

    RFG is simply an "environmentally friendlier" version of gas. In a nutshell, RFG is gas that has been supplemented with fuel oxygenates (alcohols such as ethanol and methanol). Most components found in conventional gasoline are made up of hydrogen and carbon (hydrocarbons). Oxygenates are made up of hydrogen, carbon, and oxygen, and therefore add oxygen to the fuel air mixture (hence the term oxygenates). It is these oxygenates that help turn harmful carbon monoxide emissions into harmless carbon dioxide. In fact, oxygenates actually chemically lean out the fuel/air ratio (rather than mechanically through jetting). Since these oxygenates lean out the mixture, they enhance combustion and therefore reduce emissions. Since alcohol also raises the octane level, they can contribute to a better running engine if a previously used fuel did not meet the minimum octane requirements for that particular engine. I should point out at this time that OCTANE DOES NOT BOOST POWER. It simply allows your engine to reach the performance that it was designed to operate at. Using a higher octane fuel than your engine requires will do nothing to increase performance.

    So what's the difference between ethanol and methanol? Ethanol is a grain based alcohol and methanol is ether based. There are two types ether based RFG's -- Methyl Tertiary Butyl Ether (MTBE) and Ethyl Tertiary Butyl Ether (ETBE). While both ethanol and methanol are alcohols, methanol is more sensitive to water than ethanol. Methanol is also not as compatible with engine fuel systems as ethanol and thus you can't use as high a concentration. Also, RFG's have a considerably shorter shelf life than conventional gasoline (90 days is considered the practical limit). This means that if you are using this fuel and leave your boat unused for prolonged periods, you will have to add stabilizers during the boating season. It also means you must keep your tank topped up because of condensation problems associated with these fuels (discussed later).

    It is also important to know that alcohol is a *solvent* and as such acts as a detergent in your fuel system. While this sounds just like what the doctor ordered, it means that using this fuel for the first time will likely result in filters repeatedly plugging up as dirt and gum are dissolved from the boats fuel tank and lines. Since I have already warned of potential water problems associated with this fuel, it's wise to ensure that new water separating fuel filters are installed prior to it being used and that these filters be inspected and changed regularly. In older boats, and system of parallel filters is recommended.

    Now for my personal opinion of these fuels....Why don't we want alcohol based fuels in our boats? For starters, the last thing we want to do is lean out the air/fuel mixture in our engines. Marine engines are finely tuned high-performance beasts that already test the limits of their endurance doing what we ask of them. To add a further uncertainty of too lean a mixture is pure suicide (especially in outboards). Also, as previously stated, alcohol attracts and holds moisture. This is great if you want to remove water from your car's fuel tank but not so great when you think about where we use our boats - around water. This trapped water will corrode any steel fuel tanks/lines/fittings in your boat which may result in a fire hazard. Furthermore, depending on how much alcohol is present in the gas, the amount of water it holds may be too much for the engine to burn without experiencing negative side effects (rough idle, hard starting, high speed missing etc). Aside from the water problems, the alcohol itself presents a problem in that it attacks rubber and some kinds of gasket materials (remember, it is a solvent). Again, this is a safety issue in that it can lead to an onboard fire, but it also becomes a maintenance issue if you have to start replacing the aforementioned parts.

    A new edit for 2018: The current buzz prase for the snake oil salesman these days is preventing "phase separation" in alcohol blended fuels.  Essentially, an alcohol blended fuel can only absorb so much water and when it reaches its saturation point, it drops it to the bottom of the tank.  Now you have an alcohol water solution surrounding your fuel pick up, and fuel only on top.  Oops, time to call Sea Tow.  I bet the solution from the snake oil salesmen would be to add more of their product, which likely contains more alcohol, to increase the volume of water the fuel can hold.  Seems like a backward approach to the problem - how about not having any alcohol at all, and therefore not sucking in every molecule in the vicinity into our fuel in the first place?

    Here's something that you won't hear discussed much about RFG's: they have less BTU's than conventional gas. To the layman, it means you will probably experience a small loss in power while using these fuels. Engines with onboard ignition/fuel management systems (Current EFI/DFI models) will likely automatically compensate by increasing the fuel volume or retarding the timing (since the fuel itself will burn leaner and the onboard systems will identify and correct this condition) and you will likely burn slightly more fuel as well. For example, if you used to cruise at 3000 RPM and travel at 25 mph, when using RFG's you might find that you had to increase the throttle setting a small amount to achieve the same result with an RFG. Although I have seen no definitive study supporting this, I suspect that the increase in fuel economy and decreased emissions that cars experience with RFG's will be unseen in boats because the increased quantity of fuel required to maintain performance levels will erase the reduced pollutants linearly (eg. when we advance the throttle to compensate for the power loss, the increased emission resulting from the higher throttle setting will negate the benefits of the oxygenated fuel). Here's something else to think about -- MTBE is also a dangerous pollutant and it's now turning up in California reservoirs used to store drinking water. It seems in our zeal to rid the planet of one pollutant (lead), we've simply replaced it with another.

    In my opinion, stay away from ALL alcohol blended fuels and octane boosters. Buy a minimum octane of 89 from a reputable dealer and get back to trouble free boating. When you get right down to it, why on earth would anyone buy (sometimes) cheaper blended fuels to save a few cents per gallon when the ultimate saving at the end of the summer will be pocket change? Factor in the added grief these products may cost you in the long run and good ole' high test is lookin' mighty inexpensive. ;-)

    Happy boatin'

    Dave Brown

    Brown's Marina Ltd.

  • Pre-Ignition

    What is pre-ignition and/or detonation?

    Probably the most common (or at least commonly blamed) catastrophic failure in a gasoline powered engine is pre-ignition and/or detonation. They are often used interchangably by mechanics and laymen alike, but they are two very distinct problems that I will attempt to explain as follows:


    By definition, pre-ignition is ignition of the fuel/air mixture before the desired time (i.e. before the spark plug fires). If you recall your high school physics, the 'flash point' of a flammable fuel is variable on a number of factors, including temperature and pressure. There is a direct relationship between temperature and pressure such that as pressure increases, so does temperature (conversely, as pressure is reduced, temperature drops). When the fuel/air mixture is introduced into the combustion chamber of an engine, it is subsequently compressed to a specified ratio (called the compression ratio) and that means it also experiences a temperature increase. Without dwelling too much on what determines the optimal ratio, suffice to say that the manufacturer bases the final ratio based on a number of factors - combustion chamber design and fuel octane are probably most important. If you squeeze this mixture beyond it's operating design (by planing the heads or modifying the combustion chamber design), the fuel-air mixture will actually ignite itself without the aid of a spark plug. In some engines this is actually a designed desirable outcome - a. diesel engine operates on this very principal. To a gasoline engine however, it means certain death and it's called pre-ignition. Pre-ignition can be caused by a number of things since it is essentially a spontaneous combustion caused by 'hot spots' in the combustion chamber. These hot spots can be caused by air leaks, carbon build-up, improper or inadequte oil, too high compression ratio, too low a grade of fuel, improper carburetor calibration, inadequate cooling etc. An engine experiencing pre-ignition will see combustion temperatures rise dramatically in a very short period of time resulting in a melting of the aluminum piston. This condition usually results in piston failure either through a hole being blown in the top of the piston (as the source of the pre-ignition cuts through like a torch), or the edges melting and sticking to the cylinder walls and pinching the rings into the ring lands. Pre-ignition can lead to detonation, but as you'll see it's not the same.


    Detonation occurs when two flame fronts collide. It is similar to pre-ignition in that a hot spot ignites the fuel BUT, at the same time (or close to it), the spark plug also ignites the fuel mixture and these two 'flame fronts' move towards each other and collide. This noise can be heard as 'pinging' or 'knocking' when accelerating in a car up a hill or passing (it can't be heard in an outboard motor because normal operational noises are louder and hide it). In fact, the octane rating was specifically derived as a measurement of a fuels ability to resist or prevent detonation and it's called the Anti-Knock Index (AKI). The higher the AKI (or octane rating), the more stable the fuel thus preventing detonation. While this pinging or knocking sounds harmless enough, you have to remember you're hearing this noise outside the engine. Given that you can't even hear the violent ‘normal' explosion occurring inside a gasoline engine, imagine how much more violent the explosion is if you can hear it as knocking behind the dash of your car. When these two flame fronts collide, it's equivalent to a sledge hammer being dropped onto the top of the piston, and it's easy to see how this situation might manifest itself into engine failure. Like pre-ignition, detonation raises the combustion temperature considerably, but more notably often cracks the piston, breaks rings and ring lands, and can bend rods.

    So how do we prevent these conditions from happening? First and foremost, ALWAYS use the recommended grade of fuel for your engine. Most older outboard motors were designed to run on 89 Octane fuel, which used to be called ‘regular gas'. Nowadays, regular gas is 87 octane (and even 86 in some cases) and if it's used in an engine designed to run on 89, you have set yourself up for certain failure under the right conditions (hot days, water skiing, prolonged high speed operation etc). Your next best defense against pre-ignition/detonation is FRESH GAS. Today's fuels have a ‘shelf life' of about 3 months in summertime heat. Given that some of that time was used up in transport and storage, the means you don't have long to use it before some of the additives begin to ‘gas off' which results in - you guessed it, a lower octane rating. Also, avoid RFG (alcholol blended) fuels at all costs. Next, keep your engine properly tuned and maintained with the correct spark plug heat range installed (spark plugs are not ‘all the same'). Finally, the correct propeller pitch is imperative to ensure your engine isn't labouring and self destructing (picture a car attempting to accelerate in 4th gear from a stopped position).

    While it is often very difficult to determine what the source of pre-ignition or detonation was after a failure, a competent mechanic will ensure that possible sources are examined and corrected to ensure it does not re-occur. This includes meticulously rebuilding the engine and strictly adhering to the manufacturers specifications for clearances, tolerances, timing, and synchronization. It also means ensuring any recalls or service bulletins which have not been performed on the engine are done, as well as a visually inspection and verification that the engine is rigged properly and the correct propeller pitch is being used.

    Happy boatin'

    Dave Brown

    Brown's Marina Ltd.

  • Inboard/Stern


    First things first, let's get those gas tanks filled and fuel stabilizer added according to the directions for storage (OMC brand is called 2+4). We want them full to prevent condensation, and we add stabilizer because today's fuels can have a shelf life of only 3 months without it.

    Next, run the engines up to operating temperature to get the stabilizer into the entire fuel system, and to warm the engine oil. Next, let's change the oil and filter. The reason we want to do this before extended storage, is that the used oil has accumulated acids which can attack internal engine parts over the storage period (while I am a tad skeptical over this issue, I'm not about to question an engineer's advice). Warming the oil makes it easier to change and suspends the sludge resulting in a cleaner change. Since you're gonna change your oil anyway, we might as well do it now. Don't forget to replace the filter and don't scrimp on the quality. A couple of bucks saved is hardly worth the effort when you look at what you're risking.

    Your engine is equipped with a special fitting for getting the oil out via the dip stick tube with a special pump (attachable to an electric drill and available at your dealer). The fitting you attach it to looks just like an garden hose end (which is exactly what will fit onto it). On Mercruiser, the dipstick and drain tube are one and the same. On OMC's, we made some models the same as Merc, and some with a second tube and cap specifically for draining the oil. Since writing this 15 years ago, things have changed so please consult your owner's manual for how to pull the engine oil for your engine.

    Either way, the oil cannot be changed without some sort of suction pump and proper fittings as there is no drain plug in the oil pan (like you would want to drain your oil there anyway ). Prior to about 1976, neither manufacturer had what I just described, and we have to use a glorified straw that went down the dip stick tube which always leaves you with the uneasy feeling that you didn't get it all (since it's difficult to tell whether or not the straw is at the bottom of the pan or curling around and coming back up again). On these older models (not applicable to most) there *is* a drain plug and if you get a heavy duty garbage bag, you can drain the oil into the bag and *carefully* remove it from the bilge. It's surprising how the tiniest hose clamp sticking out will easily tear open your bag of oil sending it into your bilge .

    Refill your engine with the oil the manufacturuer reccommends. OMC Cobras take SAE 30 weight oil for us Northerners, and those in the warmer climates should consider SAE 40. Mercury reccommends a 25W40 but BEWARE this as this is NOT car oil - it's a blecnd of 2 differenbt types of oils with anti-foaming agents specifically designed for the environment they operate in. If you use car oil you rish engine damage. You have been warned. No debate on what oil to use please -- read your manual and use what it says.

    Again, do not scrimp on quality in this area -- think of how important the job oil must do and how little difference there is in price between the good stuff and the cheap. I use name brand OEM oil in all the engine brands we store. Don't forget to start the engine and get the filter full again before checking the level (the engine should sit for a full minute after shut-off before taking the reading off the dipstick).

    Fogging the engine

    First, pull the flame arrester (breather), restart the engine and pour or spray in a storage fogging oil (OMC calls it just that). Not knowing what some instructions might say on some brands of fogging oil, you should do the following: Raise the idle to about 1500 RPM and begin spraying in the storage fogging oil in sufficient quantity to slow the engine to about 1000 RPM. This ensures you will get in as much oil without loading and stalling the engine in the process. If you think you're doing the engine good by dumping oil in to stall the engine, think again. This can cause something called hydro locking and can split a cylinder, break a piston or bend a rod. Seen it, fixed it, lectured endelssly about it.

    So what's this stuff do? It coats the intake, valves, pistons and cylinders to prevent rust and corrosion from taking their toll over the storage period. It's an absolute must if you want to keep your engine from seizing, especially if you plan on leaving it moth-balled for a long period of time.

    After you have a good white smoke pouring out of the exhaust (and have injected about 8 to 10 ounces of fogging oil), simply grab the choke plates and close them manually to stall the engine (or simply have someone shut the key off). The reason for using the choke is that you can continue adding fogging oil while you do it. If you use the key, by the time you get out of the bilge and up to the dash, the engine will have cleared a lot of the fogging oil. Now it's time to get the boat out of the water (unless you've already got it out and were using a flushing attachment to get this far).

    Changing lower unit oil

    Let's start by lowering the drive(s) and draining the gearcase oil into a suitable container. Since we're trying to cover all the bases, here's at look at what we should be draining and where to find the screws on all brands (I'm not up on the newest Merc's, so those in the know feel free to correct or add to the post and I'll incorporate it for next time). BTW, if the oil is at all creamy or milky, get thee to a dealer or post back your troubles and I'll see what I can do to help.

    • 1. OMC Stringer mount stern drives -- pre 1976 (the one with the big rubber boot in the transom): There are two reservoirs to drain -- the upper gearcase, and the lower gearcase (each is independent of the other). The upper is drained by a screw on the starboard side of the upper housing, and a dip stick in the top center. The lower gearcase is drained by a screw near the leading edge of the *bullet* and also one just above the anti-ventilation plate. Always fill from the bottom hole until it comes out the top one (or up to the proper level on the dipstick). New screw gaskets are strongly recommended for ALL screws.
    • 2. OMC Stringer mount stern drives -- post 1976 (still the one with the big rubber boot in the transom): #1 above applies, but there are two more reservoirs that previously weren't drainable without disassembly. The first is the tilt clutch (the thing with the tilt gear sticking out of it) and the drain screw is located right on the bottom with a vent/level screw on the side about 2/3 up.
    • The other reservoir is a little tougher to find as it is within the intermediate housing that connects to the bell housing on the engine. The drain is accessed from the outside of the boat on the starboard side of the unit. It is located where the shaft runs through to the engine and looks just like all the others. The vent/level screw is located at the top of the intermediate housing and is easy to spot as it is much larger than all the other screws. Same filling procedure for these two reservoirs -- from the bottom up.
    • 3. OMC Cobra 1986-1993 There is only one reservoir (the upper and lower gearcase share oil). There are, however, three screws. The drain screw is located in the *bullet* at the bottom, and the vent screws are located midway above the anti-ventilation plate and at the top center in the form of a dipstick. Pull the top and bottom screw to drain, but refilling requires that you install the bottom screw first, then fill the entire drive from the middle screw only until you get the proper reading on the top dipstick.
    • If the unit is filled incorrectly, an air pocket will form inside the drive such that when it *burps* up at a later date, will result in the upper oil level dropping thus destroying the top gears. Trust me on this as I have made quite a bit of money on people who were unaware of this procedure (they now leave their boat in my care ). Again, new gaskets are advisable on the screws.
    • 4. Older Mercruiser (MCM Ia, Ib and early Ic's): Same as #1 above (two reservoirs) -- one upper and one lower gearcase. Only difference is that the upper gearcase has top screw on the side and you fill it until it runs out there.
    • 5. Most other Mercruisers (later Ic's, I, II, & Alphas): Common reservoir throughout with only a lower screw on the bullet and one at Same as #3 (Cobra) except that you don't have to worry about the air pocket problem and the top screw is at the side. Simply fill from the bottom until it comes out the middle, plug the middle, then continue filling from the bottom until it comes out the top.
    • 6. Mercruiser Bravo (four models now I believe -- the Bravo I, II, III and the BlackHawk): Same as 5. except the drain the Bravo I is accessed by removing the prop -- it's at the bottom of the exhaust housing.
    • 7. Volvo 280/290 (white): One reservoir , one bottom screw and one top (dipstick like OMC).
    • 8. Volvo/Cobra SX 1994 and up (grey): Same as 3. (Cobra and Volvo manufacture this drive together)

    So what lower oil should we use?

    On OMC electric shift models, you MUST use something called Type C (now called Premium Blend) in the lower unit only (absolutely no substitutes allowed, period). All other OMC reservoirs and models should be filled with Hi-Vis or the new Ultra-HPF synthetic. For Mercruiser use OMC Hi-Vis, Ultra-HPF, or Quicksilver Gearlube (or their synthetic blend called High Performance Gear Lube). Volvo 280/290 originally called for SAE 30, but I strongly recommend moving to Hi-Vis or better yet Ultra-HPF. Volvo SX and Cobras use Ultra-HPF Synthetic.

    My advice is to use Synthetic gear oils whenever possible. Actually, my stronger advise is to RTFM and see what it calls for -- I have seen engineering reports which shows gear and bearing wear is reduced up to 50% over conventional oil, and it does not break down under stress and heat like conventional oils. As for getting the stuff in, all manufacturers offer an inexpensive plastic pump which fits into the oil bottle. Count on using at least 70 ounces to completely fill any drive.

    Annual drive maintenance

    While we're talking about drives, now's the time to pull it and grease the U-joints (OMC stringer mounts do not have them, so ignore this if you own one). First of all, this is a two person job for the inexperienced. In fact, I don't think this should be attempted the first time without someone present who has done it before:

    On Cobra drives, remove the six mounting bolts and rear trim cylinder retaining shaft, the pull on the drive (careful, they're heavy! ) The grease nipples may have to be turned to 45 degree angles to get the grease gun on it. Use this opportunity to grease the gimbal bearing as well so you can see when it is filled. The nipple is located near the transom on the starboard side of the transom bracket.

    Grease the splines of the *donkey dick* with OMC molly lube, and oil the shaft, o-rings, and outer diameter of the U-joints with oil to aid re-installation. Place a new gasket on the studs, and re-install the drive using a large screwdriver jammed into the U-joints to turn the shaft back and forth to get through the bellows and align the shaft.

    All of this will be very clear when you have the drive off. If you're at all uneasy, a dealer will probably charge $30 to do it and may let you watch (I do). In fact, I will have the customer help if he likes so he can learn. Pulling the drive now on an OMC may also save some aggravation later. If the gasket hasn't sealed perfectly (and the early ones often didn't) the shift linkage pocket fills with water.

    While the gaskets seems poor at keeping water out, it seems to do a good job of keeping it in and if this freezes, you'll get a nasty (albeit cosmetic) crack in the side of your drive. Pulling the drive automatically drains this pocket. If you're not going to pull the drive, you merely have to loosen it for this pocket to drain. Newer models incorporated a drain plug at this spot, but since I recommend pulling the drive to do the u-joints anyway, we won't have to worry about it.

    On most Mercruiser drives, the same applies as above (including greasing the gimbal bearing) except the drive MUST BE IN FORWARD GEAR. Failure to put the drive in forward will not only make it tough to remove, but shift parts WILL BE DAMAGED if you succeed. For re-assembly, make sure the drive is in forward and use the prop to help align the splined shaft into the engine coupler. If you've got a Bravo drive, the shift requires a special release procedure and many of the new Merc's have sealed u-joints so unless you want to check bellows integrity, no need to be in here anyway. MAKE sure that the quad ring (4 sided circular ring, like an O-Ring) gets replaced and properly glued into place EACH time the drive is pulled.

    Merc makes 3 different "Kits" for this purpose, MCM "I" drives thru 1984 (PRE Alpha drives) 27-64818A1 and 27-94996A1 for Alpha and The Second Generation Alpha (AKA GEN II) uses a different gasket due to the remote gear lube bottle. I will get that # if anyone is interested, just have don't have it on hand at the moment.

    On Volvo 280/290 drives, the U-joints are sealed and even if you wanted to get in there to check them, it's not for the back-yard mechanic. Leave this one to the pros.

    All brands should have their bellows changed at least every five years. I've got plenty running on their original at twenty years old, and just replaced one the other day that failed after three years. Bellows replacement is not for the faint of heart so unless you have at least a basic idea of what to do, leave this to the pros. It's also harder to do in the cold so let's talk about it next spring when it's nice, but still early to boat. :-)

    As for impellers, one year, five years, ten years whatever. I've plenty still running on the originals, but I know there are plenty of maintenance freaks in here who like to do it annually. Whatever turns your crank. :-)

    Back to the engine

    So what anti-freeze should we use? Technically, if an engine is drained properly, you don't need *any* anti-freeze (which is why you won't see it in the service manuals). Personally, I like to get anti-freeze in there to mix with any water that may have been missed, and to provide the inside of the block with protection from corrosion. Also, I use regular toxic ethylene glycol anti-freeze (mixed 50-50 with water) because it's just plain better at protecting your engine.

    I do not, however, allow my stored engines out in the spring without removing it first and recycling it for use again next year. If you're just gonna start your engine next spring without removing the anti-freeze, obviously you should use propylene based non-toxic anti-freeze.

    But before you do, bear in mind that while it may be non-toxic , (‘less' toxic actually) IT IS STILL ILLEGAL to dump foreign substances in the water, whether it is toxic or not. I do not tolerate such actions at my ramp and have little respect for anyone who does. If you've been guilty of such practices in the past, you know better now and should change your ways. Think about how irresponsible people are ruining it for all of us and if you see someone else doing it, report them immediately.

    If you choose non-toxic anti-freeze, DO NOT USE PLUMBING ANTI-FREEZE. It attacks the rubber seals in the engine water pump and since it already comes ready to use it raises a raises a further concern -- What happens if it meets and mixes with a water pocket? It's possible the solution will be significantly weakened in this area of the block which may not provide the proper protection needed. Food for thought. An interesting side bar — even if you use non-toxic in the fall, it will BECOME toxic over the storage period due to migration of the nasties they're making those marine gaskets out of nowadays. I therefore repeat myself - get the stuff out before starting in the lake - it's toxic as hell anyway you look at it.

    Time to get that water out of your engine so let's locate your drain cocks. As a GUIDE line, here's where to look: 4 & 6 cylinder in-line engines: one drain on the block, one on the manifold (usually on the port side).

    6 & 8 cylinder V-block engines: two drains (on each side of the engine) and one on each manifold (sometimes this is simply a bigger rubber cap and hose clamp).

    Older Mercs (shudder) had a multitude of hoses and drains (the 888 causes me to cringe).

    These drains are usually brass cocks, but sometimes they are just threaded brass plugs (and are sometimes painted thus making them difficult to see). Always remove the whole thing (even if loosening appears to get the water flowing). There is a tremendous amount of rust and corrosion laying behind them and you must ensure that the way is clear for them to drain completely. I shouldn't have to remind you what will happen if you don't. The next part gets a little tricky because of the number of variations out there, so I'm going to stick with the basics and anyone with something different can post back and I'll offer advice on an as needed basis.

    *Most* modern engines have a main line running from the water pump in the lower unit up to the thermostat housing. Find this hose first and remove it from the thermostat housing.

    NOTE: There is absolutely no need to remove the thermostat housing to winterize your motor. The guy who told you this doesn't know what he's talking about. Are we clear on this?

    Using a funnel, pour anti-freeze into this hose and keep going until anti-freeze comes out the water pick-up in the lower unit. The anti-freeze will not only push the water out, but it will also flush the power steering cooler (located in-line of this hose) and the water pump thus we kill three birds with one stone. Now there's no need to locate and attempt to undo the little plug on the collar -- trust me.

    Next, remove the two hoses running to each exhaust manifold at the thermostat housing. Pour anti-freeze into the hose until it comes out the manifold drain cock, then install & tighten the drain cock. Continue to fill the manifold with anti-freeze until it comes out the prop. Repeat this procedure for each manifold.

    Next, pull the large diameter hose from the thermostat housing (that connects to the engine water pump). Begin filling this with anti-freeze until it starts coming out the drain cocks. Install and tighten the cocks and continue filling until the block is full. Reconnect all hoses and tighten clamps. Anyone who has more hoses or isn't clear on what I've said, please post back and ask for a clarification as I will continually update this post for future release. Newer Volvos, some Mercs, and all straight shaft inboards have an engine mounted water pump. The smart people reading this will be able to apply what I've already posted to their situation. If dumb ones should ask themselves why they're attempting to screw with a very expensive part of their boat to save a few bucks.

    Plumbing Systems.

    First, let your taps run to drain the main holding tank (don't forget to shut off power to the hot water heater). Next, drain the hot water tank (small drain cock at the bottom and lever vent at the top). Remove both water lines from the tank and devise a method of connecting them together (using an elbow from the tank etc). The reason for this will become clear later.

    Now go to your pressure pump and holding tank (they will be close together). If possible, remove the line that runs from the tank to the pump (at the tank end). If the line is long enough, merely redirect the line into a jug (or pot, or bowl) of plumbing anti-freeze. If it's not long enough, find a way of making it so. Turn on the power to the pump and open only one cold water tap until the system primes itself. Allow it to run until anti-freeze comes out the tap. Shut off the tap and turn on the hot water tap until anti-freeze appears (this will take slightly longer as the path is usually longer). Repeat this procedure for every tap (hot and cold done separately) and shower (and the toilet if it's part of the pressure system).

    Don't forget about the ice maker in the fridge, the sink in the v-birth, or the shower or external tap on the stern of the boat. Make sure you keep your anti-freeze supply above the hose end to prevent you having to reprime the system. When you're done, turn the pump off and reconnect the line from the pump to the tank -- job done (leave the hot water tank by-passed until spring).

    Now you're probably asking why we haven't put any anti-freeze in the hot water tank or the main water tank and the answer is simple -- we don't have to. Both tanks are sufficiently drained such that they will not incur any freezing damage, and by not filling them with anti-freeze, we don't have to worry about tasting the stuff for the first month(s) next year. Non-toxic or not, the stuff tastes and smells awful. To start the system up in the spring, merely fill the water tank with fresh water, open all taps one at a time to clear the anti-freeze, then hook up the hot water tank hoses again.

    Now the system is completely purged of all anti-freeze ensuring no lingering smell or aftertaste. This method is not only quick, it's also the best way (by far) to winterize your plumbing. Stay away from marinas who merely pour gallons and gallons of anti-freeze into your holding tank. Not only will it get diluted by any leftover water (and thus not adequately protect) but the taste will linger forever in your water. My method will use less than 8 liters (2 gallons), where some marinas will use up to a case (or two) under their method.

    Since the toilet is usually supplied from a sea cock (erotic sounding, eh?) in the hull, we must find and access it. Once found, undo the hose clamp and pull off the hose. If you're still in the water, don't forget to close the seacock.

    Place the hose in the anti-freeze jug (engine anti-freeze works fine here and is cheaper to use). Go to the toilet and operate the pump until you have sucked out all the anti-freeze out of the jug and passed it to the holding tank (which you hopefully had pumped out while it was still at the marina). Reconnect the hose and you're done (leaving the sea cock closed if you're in the water, open if you're not). The floor is yours Peggy if you'd like to add more here.


    I strongly recommend the batteries be removed entirely from the boat, but if you're one of those types who leaves them in, at least disconnect them (ALL CABLES). Turning the battery switch off is not good enough. Next, clean the terminals and tops of the batteries as any moisture or dirt will allow cross discharge between the posts. The batteries should be stored in a cool, dry place. Warm humid storage will promote cross discharge through the air. Charge the batteries at least every two months. Watch your water levels and top up as necessary.

    FYI, I store over 250 batteries in an outdoor building (unheated). I ensure the batteries are fully charged prior to storage, and charge them only once in January. I have yet to lose a battery over the winter and have had some last up to 9 years before I gave it the boot. A good battery will give a least five full years of service. One more thing to try and kill an urban legend: storing your battery on a concrete floor will not hurt your battery, PERIOD.


    I'm gonna leave this up to you guys to yack about because it's more of a regional thing. Where I live, the water is clear and the algae growth minimal (God's country). We don't even bother cleaning the boats until spring, and even then, a good scrubbing and spray brings them back to nearly new.

    I will recommend hydrochloric (muriatic) acid for those stubborn stains and water lines, but be careful -- that stuff is mighty toxic to the lungs and corrosive to skin. Apply it with a paint tray and roller, let stand for 10 minutes, then rinse off. Water will quickly neutralize the acid. Don't forget to store your boat bow high and remove all drain plugs. It would be a shame if you found a split hull in the spring (well, not for me and my fellow marina operators ).

    If possible, store your tops in a warm place at home. While the new synthetics are quite durable, the older vinyls and viewtex (clear plastic) don't like the cold. Obviously, a good wash and rinse is recommended before storage. If the boat is going to be outside, it's not that tough (or expensive) to build a wooden frame (using the tent pole method with bailing twine to support). A suitable sized tarp is the best investment you can make and it can last for years if properly tied when on (to prevent flapping in the wind) and properly stored during the summer. Shrink wrapping is expensive, and not reusable.

    Have I missed anything?

    Now, about your bill...............

    Happy boatin'

    Dave Brown

    Brown's Marina Ltd.

  • Outboard


    I often hear people say they never stored their motor in the past, why should they spend time and money doing something if it doesn't need it? The reality is, improper off season storage of an outboard motor has cumulative effects. During the off season, engine components can and do rust — the extend of which depends on what fuel mixture was last running in the engine, and the heat and humidity the engine is stored in. When rust forms, it creates pitting in the metal — specifically, the hardened steel surfaces the needle bearings in modern engines utilize. When the engine is started each spring, the rust is washed away and the pitting remains until one year, the bearing calls it quits and a rod exists through the side of the block. Many people don't associate rod failure with poor engine storage because the failure often takes place in the middle of summer and no connection is made to poor storage practices. Naturally, when this happens, they'll blame the engine manufacturer instead of placing the blame squarely where it belongs.

    Modern engines, especially oil injected ones, have so little oil in them when the key is turned off, that maintenance issues are no longer an ‘if', but a ‘when' scenario. It doesn't take much math to figure out that current oil injected outboards can run on as little as one cup of oil to five gallons of gasoline. Given that current oils are designed to lubricate and burn cleanly, (not coat and protect from rust), it's more important than ever to properly store your outboard motor and protect your investment. Bearing issues aside, the are other items that need to be addressed too so let's get started:

    All Models

    To prevent condensation in the fuel tank and prevent breakdown of the fuel during storage, let's fill those fuel tanks with gas and add the appropriate amount of fuel stabilizer (follow directions on the label for storage). So why stabilize the fuel? The current shelf life of today's fuels is pegged at about three months. After that, the additives begin to separate, the octane level drops, and the gas begins the process of ‘going bad' and varnishing fuel system components (including gumming up the carb). Since most of us are going to lay the boat up for about 6 months, this step is just as important as the others in ensuring trouble free boating next summer.

    Bring the engine up to operating temperature and allow enough time for the stabilizer to reach the carbs (10-15 minutes at idle, or 3 minutes at wide open throttle). Since portable steel tanks were used for many years with outboard motors, visually inspect for water in the bottom of any steel tank(s) using a flashlight. If water is found (round globs on the bottom of the tank), dump the tank and flush thoroughly. If rust is evident, the tank should be disposed of and replaced with a new plastic style. In the water, or on a pair of earmuffs (to supply the engine with water), do the following:

    For carbureted engines with a maintenance valve (newer OMC's):

    Attach engine fogger to maintenance valve fitting (looks like a tire air valve -- check your owners manual for location). Start engine and bring RPM to about 1500. Push and hold the release button on the fogger and continue holding until a steady thick white smoke appears out the exhaust. Depending on the size of the engine, this should consume about a half a can of fogging oil. Turn the engine off immediately after you're finished fogging (to ensure as much fogger as possible remains in the engine) and remove the fogger from the maintenance valve.

    For carbureted engines without a maintenance valve (common for most brands and years):

    Depending on the engine make a model, there is either removable plastic plugs in the breather cover, small holes in the breather, or no breather at all. Since we have to spray the fogger directly into the carb throats, determine how you are going to gain access to them before you get started. If the engine is equipped with removable plugs, pop them all out now. If there are pre-drilled access holes, locate them and ensure you have as many holes as there are carb throats. If there are no plugs or pre-drilled holes, simply remove the breather cover to gain access. Install the straw adapter that came with the can of fogging oil and bring the engine up to 1500 RPM. While holding down on the release button of the fogger, spray fogging oil into each carb throat for a 3-5 seconds, then move onto the next throat. Keep going from carb to carb until a steady thick white smoke appears out the exhaust. Depending on the size of the engine, this should consume about half to 3/4 of a can of fogging oil. Turn the engine off immediately after you've finished fogging (to ensure the fogger remains in the engine).

    All Models

    Pull the boat out of the water (or remove the ear muffs) and keep the motor in a vertical position for at least ten minutes to ensure all water is drained from the block and passages (outboard motors are self draining and require no anti-freeze for storage). If possible, the engine should be stored in an upright position in the coldest condition possible (rust processes are slowed considerably at low temperatures, and no humidity to promote rust exists below freezing). The worst place to store your outboard is in your basement beside your furnace — high humidity and warmth will seize an engine in no time.

    For those that may be storing for extended periods of time or in warm humid conditions, you might want to remove the spark plugs and squirt some additional 2 stroke engine oil or fogger into the cylinders, then roll the engine over by hand to thoroughly coat everything. Re-install the plugs to minimize condensation during the storage period.

    Storing the carbs wet or dry?

    Today's carburetors utilize many neoprene, rubber, and alcohol resistant materials. Draining the fuel system for storage can put these parts at risk by allowing the materials to dry out and crack. Most (if not all) manufacturers recommend the carbs be left ‘wet' — that is, they fuel is stabilized and left in the carb during the storage period. If the engine will be stored on its side, or will be traveling in a vehicle before lay-up, it may be best to drain the fuel system by disconnecting the fuel line while fogging the engine, then continue to fog until the engine runs out of fuel (choking just as it's dying will get the last bit of fuel out).

    Gearcase Oil Change

    At a minimum, we want to inspect the gear oil before storage because if water is present in the gearcase, it can freeze and crack the case when the temperature falls (not to mention your gears and bearings will rust too). As long as we're there anyway, why not change it now too so we have one less thing to do in the spring when we're busy trying to get back on the water as fast as we can?

    Most brands have easy to find drain and vent screws. The drain/fill screw is usually located just beneath the ‘bullet' shape of the gearcase, while the vent/overflow screw is located just above the anti-ventilation plate (often incorrectly called the cavitation plate). Pull both screws and inspect the quality of the gear oil while it drains. WARNING: Do not pull the screw with the philips (star) headed screw. This part (the pivot pin) cannot easily be re-installed properly without disassembling the gearcase.

    White or creamy oil indicates you have water contamination. If you find this condition, have a dealer perform a pressure and vacuum test on the gearcase. It should go without saying that if nothing but water comes out of the oil cavity, you're likely in need of something more than seals. Grey oil usually indicates a failure of some sort has occurred in the lower unit (chipped gears or bearing failure). In some cases, prolonged use of the same oil can lead to the same oil condition. If you find you're oil is grey with a very strong odour, see your dealer for service and advice. Black oil indicates all is OK, you're just a bit overdue on your change cycle. As a benchmark for future the future, gear oil should be changed every 50-100 hours of operation, or at least once annually — whichever comes first. Many gearcases utilize a magnet on the drain screw. It's is normal to see a collection of fine metals filings, but if you find metals chunks, it's best to have the unit looked at by a professional.

    Which gear oil to use?

    If you have an electric shift gearcase (common in the sixties), you need a special oil called OMC Premium Blend (used to be called ‘Type C'). Failure to use this oil will result in a failure of the electromagnetic shift system this system utilizes.

    All other gearcases (including hydro-electric shifts) will operate on a hypoid 90 weight oil. OMC's Hi-Vis brand fits the bill nicely, and if you really want to extend gear life and protect if the unit is contaminated with water, I strongly recommend OMC's HPF synthetic gear oil. When in doubt, follow your engine manufacturers recommendations.

    Re-filling the gearcase (do NOT leave it empty for the storage period):

    To start with, let's install new gaskets or o-rings on our fill screws (cheap insurance to save grief down the road). Next, many manufacturers supply their oil in soft squeezable bottles, or optional hand pumps can be purchases for larger containers. Whatever method you choose, fill from the bottom hole until it comes out the top hole. Install the top screw, then remove filler from the bottom and quickly install the screw there as well. Torque the screws and wipe off the excess oil. Speaking of excess oil, please make sure you dispose of the old oil in an environmentally responsible manner.


    I strongly recommend the batteries be removed entirely from the boat, but if you're one of those types who leaves them in, at least disconnect them (ALL CABLES). Turning the battery switch off is not good enough. Next, clean the terminals and tops of the batteries as any moisture or dirt will allow cross discharge between the posts. The batteries should be stored in a cool, dry place. Warm humid storage will promote cross discharge through the air. Charge the batteries at least every two months. Watch your water levels and top up as necessary.

    FYI, I store over 250 batteries in an outdoor building (unheated). I ensure the batteries are fully charged prior to storage, and charge them only once in January. I have yet to lose a battery over the winter and have had some last up to 9 years before I gave it the boot. A good battery will give a least five full years of service. One more thing to try and kill an urban legend: Storing your battery on a concrete floor will not hurt your battery.


    Where I live, the water is clear and the algae growth minimal (God's country). We don't even bother cleaning the boats until spring, and even then, a good scrubbing and spray brings them back to nearly new.

    I will recommend hydrochloric (muriatic) acid for those stubborn stains and water lines, but be careful -- that stuff is mighty toxic to the lungs and corrosive to skin. Apply it with a paint tray and roller, let stand for 10 minutes, then rinse off. Water will quickly neutralize the acid. Don't forget to store your boat bow high and remove all drain plugs. It would be a shame if you found a split hull in the spring (well, not for me and my fellow marina operators ).

    If possible, store your tops in a warm place at home. While the new synthetics are quite durable, the older vinyls and viewtex (clear plastic) don't like the cold. Obviously, a good wash and rinse is recommended before storage. If the boat is going to be outside, it's not that tough (or expensive) to build a wooden frame (using the tent pole method with bailing twine to support). A suitable sized tarp is the best investment you can make and it can last for years if properly tied when on (to prevent flapping in the wind) and properly stored during the summer. Shrink wrapping is expensive, and not reusable.

    That's about it. If you run your engine in salt water, you should have thoroughly flushed the cooling system prior to starting the winteriztion of the motor. The rest of us can put the motor to bed now and rest easy our pride and joy will continue to provide many years of enjoyment to come. Have I missed anything?

    Now, about your bill...............

    Happy boatin'

    Dave Brown

    Brown's Marina Ltd.

  • Types of Anti-Freeze

    Types of Anti-Freeze and their application

    Is all anti-freeze the same? Many people mistaking believe all engine anti-freezes are the same when, of course, they are not. The green glowing toxic stuff that we all know and love is Ethylene Glycol. It offers excellent protection for your engine (both against freezing and corrosion), but it's not the sort of thing you want to introduce to the water supply every spring (or your digestive system, like I once did -- but that's another story). The 'less toxic' stuff is Propylene Glycol and while it is less nasty than the Ethylene, it isn't exactly sugar water either. In fact, here's what the warning label says on a bottle of Propylene Glycol:

    Cautionary Information: This product contains propylene glycol and is not considered toxic according to the regulations of the Consumer Products Safety Commission. All ingredients are generally regarded as safe in the US Federal Register and by the Food and Drug Administration. It is, however, not intended for human or animal consumption. This product may be harmful if swallowed. Store safely away from children and pets. Do not store in open or unlabeled containers. Clean up any spills or leaks.

    Both types of anti-freeze coolant are blended with stabilizers and rust inhibitor additives and can both do the job intended. Plumbing anti-freeze (usually pink or purple) can be either Propylene based or alcohol based. If it's alcohol based, it should not be used in engines as a coolant as the alcohol will attack rubber seals and hoses. Also, its protection is dramatically reduced if it mixes with water and thus is not a good choice given what we're trying to achieve here -- freeze protection.

    So what anti-freeze should we use to store your boat's engine? Either Ethylene or Propylene glycol will work fine but remember, whatever the toxicity antifreeze you put in, it will most certainly be more toxic when it comes out in the spring due to the migration of some nasty chemicals they're using in marine gaskets. Also, since it is illegal to dump any foreign substance in any waterway (toxic or not), you have the responsibility, both legally and morally, to remove and recycle your anti-freeze prior to launch.

    Now, a thing or two about freeze protection:

    Most people assume that the freeze rating on the jug of anti-freeze meant that you were protected to that temperature (e.g., the anti-freeze did not freeze until that temperature was reached), The fact is, winterizing products are rated by burst protection and not freeze protection. So when we say that an anti-freeze solution will protect our copper plumbing pipes to -50 deg F, it means that a copper pipe filled with this product will burst at -50 deg F. The actual solution will start to form ice crystals at approximately +12 deg F. As the temperature drops, the solution continues to form more dense ice crystals and expands. As the solution expands, it puts more pressure on the pipe and at -50 deg F, the pipe will burst. A PVC pipe will burst at -15 deg F since it's not a strong as copper pipe.

    Since a stored engine is not being used, it is not necessary to keep the system ice crystal free, only to keep it from bursting at a rated temperature. While you can buy more expensive, lower rated antifreezes, you really only need to protect yourself from burst pressure. By the same token, why not spend a couple of extra bucks buy the lowest rating available (especially given the result of a miscalculation). It's cheap piece of mind considering the cost of miscalculating your needs.

    Happy boatin'

    Dave Brown

    Brown's Marina Ltd.

  • Silverline

    Whatever happened to Silverline, Vanguard & Invader Boats?

    I often get requests from Internet surfers looking for parts and information for Silverline Boats. The company that manufactured Silverline in the 70's and early 80's was Larson and they stopped circa 1982. The name was sold along with the other assets at liquidation and is currently owned by Canadian manufacturer InterNautic Marine (formerly Odyssea Marine, which was Centurycraft before that, which was Vanguard Boats before that). InterNautic ceased production at the end of 2005 due to weak sales in the fiberglass market and there are no plans to start up production in the near future as far as I know (we were a Silverline dealer for 12 years until production ceased). Their website has not been updated in some time (although the company still exists and is owned by Arow Global). InterNautic has no knowledge or parts of the Larson era Silverlines so your search stops here and now for the old guys. For Silverline, Invader & Vanguard lines produced in Manitoba, Ontario, Canada in the late 80's and up, there are NO parts available. However, Starcraft has produced a 'flip' of the 1700 model hull (naughty boys!) and many of the parts look like they'll fit.

    That being said, boat manufacturers rarely actually produced anything more than the hulls and upholstery in-house. Most of the windshields, cleats, instruments, convertible tops, horns, switches etc. were made by other manufacturers, many of whom are still in business and can provide replacements. If you're looking for a new convertible top or seat work, simply take the boat to a shop that specializes in custom marine upholstery. Want graphics? Check your yellow pages for businesses that supply custom decals (it's amazing what they can reproduce). For the other stuff like instruments, accessories, bilge pumps, rub rails etc., see your local marina as they have catalogues filled with everything you'd ever need.

    For engine parts and information (including wiring diagrams), contact your engine manufacturer dealership as applicable. There is no such thing as an owner's manual for Silverlines of any year (in fact, most boat manufacturers simply produce a generic ‘safe boating' booklet - not a guide to how things work on small boats). One of these days I'll get around to producing a downloadable generic wiring diagram that should help most people, but today isn't the day. Best of luck in your search.

    Dave Brown

    Brown's Marina Ltd.