Disclaimer: The following procedure has served me and others well.
The author has followed it to winterize my tournament inboard boat and perform
some of the recommended annual maintenance for several years now. While this procedure has worked well for me,
the Tyler Ski Club and the author make no
guarantees or warranties as to its universal reliability in or effectiveness to all applications. If you have any doubt concerning
your ability to do this job yourself or as to the reliability or completeness of the information presented here, please consult
a professional marine mechanic. Good luck.
to the gas tank. Use a fuel stabilizer that is designed
for ethanol blended fuels.
2. Warm up the engine to operating temp and change the oil and filter.
You can use a
drill pump to
expedite the process. Replace with amount specified by the engine manufacturer
(some of this will be poured directly into the filter before installing it). Engines with flat tappet cams, i.e., Fords and
possibly some pre Vortec Chevys, should use an oil containing the zinc additive ZDDP such as
Valvoline VR-1 Racing Formula 20W50.
3. Warm up again if necessary and change Transmission fluid. Keep track of how much comes out and replace it with the
same amount of Dexron/Mercon (your transmission may require something different depending on your manufacturer.
4. Warm boat back up to operating temperature, lift the flame arrestor up, and fog throat of carb/throttle body intake
until it smokes or the engine dies (approximately 10 seconds or 1/3 can). Kill the engine. Do not fog dry intakes such as
the PCM GT-40.
5. If you are going to add antifreeze, drain the block first; RV
antifreeze should not be diluted. Then, reinstall the
drain plugs. You can add antifreeze in a couple of ways.
You can add 5 gallons of
Pink RV Antifreeze
or Sierra (propylene glycol) to a bucket and suck it up
with the intake hose; fogging as it runs out. Alternatively, you can add antifreeze by pouring the antifreeze into the
hose leading to the thermostat housing through a funnel. Roughly
3 gallons of antifreeze is required if you do it this way.
With PCM marinizations, there is a bypass that will allow the
antifreeze to get to the block even if the engine is not warm.
With other marinizations, warming up the engine is advisable if
you use the "pour in" method. Note: RV Antifreeze may not
be recommended for boats with Aluminum heads.
6. If you have a metal flame arrestor, spray the flame arrestor from the inside out with
carburetor cleaner. Dry thoroughly
before you reinstall it.
7. If you don't add antifreeze, pull the two plugs on either side of the engine block and remove the plugs on the back
of the exhaust manifolds. On PCM engines, there is another plug in the piece connecting the hoses coming from the thermostat
housing and going to the engine block. If fuel injected, removing the starboard side block plug may involve removing the
knock sensor. Use a coat hang wire to make sure the openings are free of rust particles and debris. Wrap the plug threads
with Teflon tape so they won't be hard to remove in the future (you'll be excited in the spring and won't want to do this).
Put plugs (including bilge drain plug) in a plastic bag and zip tie it to the steering wheel so you won't forget to reinstall
the plugs come spring.
8. If you haven't added antifreeze, disconnect the raw water hoses at their low points and shake them a bit. Blow through
them if necessary. Remove the hoses from both sides of the transmission cooler. Make sure the transmission cooler doesn't
have debris in its screen. Leave the hoses disconnected. Remove cap and screen from raw water strainer and make sure it
doesn't have any water sitting in it.
9. Remove engine kill switch and spin the engine over for a few seconds to remove excess water in the pump bodies. Reinstall
the kill switch so you don't lose it.
10. Remove impeller if you don't plan to replace it in the spring. Keep this impeller in the glove box as a spare if
you need one. If you have a PCM Ford with a Sherwood
pump, you want
this impeller. If you
have an Indmar engine (Chevy or Ford), you'll need
11. If you have pitot style speedometer pickups, with a needle, check the pickups to be sure they are not blocked. Next,
remove the speedo lines at the front of the boat and blow the water out of the lines and ballasts. Reconnect them when you're
12. Wash and Wax boat. Vacuum the carpet. Spray the seats down with
303 Aerospace Protectant or comparable vinyl protectant.
13. If you did not add antifreeze, drive the boat around on the trailer for a bit (at least 15 minutes). Make sure there
are some hills. This will allow things to drain. Once you do this, you can put it in the garage. The rest of the procedure
can be done inside.
14. Clean/Wipe down motor and bilge.
15. Disconnect the battery (always remove negative terminal first, then remove the positive terminal) and put it on a
battery maintainer/charger. Store it in a cool, dry place.
16. Some manufacturers recommend that you service the starter.
On the advice of a trusted marine mechanic/friend, I never
bothered. But if you're so inclined, with the battery disconnected, remove the wires from the starter. Remove the starter and inspect
it for damage and rust. Rotate the gear so it climbs the shaft and lube the shaft with light grease. Let it return to its
normal position and move it up a couple of times. Grease the gear, reinstall it and reconnect all cables and wires. Note:
I have never done this. My local dealer insists that it is not crucial.
17. Lubricate the trailer winch and any other moving parts on the trailer. Grease the wheel bearings
multi purpose marine grease. Some suggest reducing
the tire pressure to 25 psi to takes some pressure off the sidewalls. Others suggest that the tires need to be over inflated
for storage. The safest bet is to put the boat on jack stands and just take all the weight off the tires completely.
18. Remove the spark plugs and spray
fogging oil into the holes. Afterwards, turn the engine over by hand a few turns.
19. Spray down the engine's metal surfaces with
20. Prop the motor box up at least four inches. This keeps condensation from collecting in there, which can mess up the
starter and other things that rust.
21. If you have problems with rodents or the like, put duck tape over the exhaust flaps.
22. Put the cover on the boat.
*For those of you with carbureted engines, I have it on good authority that you're less likely to have any problems if,
during the winter, you crank your boat once a month and let it run for a few minutes. Don't forget to redrain the block and
exhaust if you decide to do this. Rebuilding carbs can be expensive if you're not the DIY type and time consuming regardless.
**There are other items constituting periodic maintenance that are not listed here or which I do in the spring. Consult
your owners manual to determine what is recommended for your boat.