Add Fuel Stabilizer and CirculateEdit

Let's get those gas tanks filled and fuel stabilizer added according to the directions on the bottle for storage. We want the tanks full to prevent condensation, and we add stabilizer because today's fuels can have a shelf life of only 3 months without it. Not stabilizing the fuel can cause everything from gummed carbs or injectors to engine failure. Need I say more about its importance?

Next, run the engines up to operating temperature to get the stabilizer into the entire fuel system, and to warm the engine oil (a quick loop around the lake speeds this up and gives you one last chance to feel the win in your hair - if you have any)).

Change the Oil and FilterEdit

Now it's time to change the oil and filter. The reason we want to do this before extended storage, is that the used oil has accumulated acids and carbon deposits which can attack internal engine parts over the storage period. Warming the oil makes it easier to change and suspends the sludge resulting in a cleaner change. 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 (i'm going to harp on this continually throughout).

Most engines are equipped with a special fitting for getting the oil out via the dip stick tube with a special pump (attachable to an electric drill or vacuum pump available from 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. OMC's made some models the same as Merc, and some with a second tube and cap specifically for draining the oil. Newer Mercruisers (2002 and up) have a hull drain feature that allows oil drainage right out the back of the boat without a pump. Check your owner's manual for instruction on this method. And just to give you some trivia to keep things interesting - the reason for coating the oil filter o-ring is NOT so it seals, it's so it doesn't stick itself to the block making it impossible to remove next time. If you didn't know this before, please mail me $5 cash at the address below.)

Prior to about 1976, neither manufacturer had what I just described, and we have to use a glorified straw that goes 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 (that means THICK, not dark green), 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 SAE 30 weight oil OR a multigrade that is marine spec (Like Merc's 25w40). 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 OMC Cobra oil in all the engine brands we store (it's SAE 30). 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 EngineEdit

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.

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 if it's fuel injected). 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. DO NOT stall the engine by pouring excess fogging oil in at the last second. You risk 'hydraulicly locking' the engine and severely damaging it. 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).

Change the Lower Unit OilEdit

Let's start by lowering the drive(s) and draining the gearcase oil into a suitable container (and disposing of it responsibly later). Use your owner's manual as a guide - it would be hard for me to describe all types and procedures here (although I'm going to try). If the oil is at all creamy or milky, get thee to a dealer - you need to have it checked.

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: 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. Newer models also have an additonal reservoir mounted to the engine inside the boat. Make sure this is OVERFILLED when you're done as an air pocket will burp in the first 50 hours of running next year dropping it to the normal level.

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- 1997 (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 OMC/Bombardier 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 their High Perforamnce Gear Lube (a synthetic), or Quicksilver Gearlube . 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.

My advice is to use Synthetic gear oils whenever possible. Actually, my stronger advise is to RTFM (Read The Friggin Manual) 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 MaintenanceEdit

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, then 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 $40 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 (by rotating it) 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 (update - this gasket is now the same for both drives).

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 in my opinion. Every 5 years is a good guideline :-)


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 going 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. This isn't just a legal issue - it's a moral issue. If that doesn't make you think twice, then do it for selfish reason - you and your family play in that water.

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.

  • 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. 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. 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 SystemsEdit

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.


This is more of a regional thing. Where I live, the water is crystal 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.