Winterizing Your Boat

First and foremost, if you are new to boating, please take your boat to a trusted professional to winterize your boat. This step of maintenance is quite likely the most important, and some insurance companies will not pay for lack of maintenance.

That being said, if you are an experienced boater and know the workings of your boat this could be quite helpful and help cut down on maintenance costs. There are 3 types of engines I will discuss for winterizing, Inboard engines, Inboard/Outboard engines and Outboard engines. If your boat is used in a saltwater environment, first flush the system with fresh water to help push out the corrosive saltwater. You can do this using our motor flusher attachment. Then proceed as follows.


First add fuel stabilizer to the fuel tank. It is important to follow the steps written on the bottle to make sure you add the appropriate amount of stabilizer to fuel. It is recommended to keep the fuel tank as full as possible when in storage to minimize condensation that can build in your fuel tank. Start and run your engine making sure to supply the engine with adequate fresh water to keep the engine cool. Bring the engine up to operating temperature and shut off. Now change the engine oil and oil filter. (Shown here if needed). Now remove the engine block drain plugs, as well as all other drain plugs as indicated in your owner’s or service manual. If you need a manual click here. Remember to drain all accessories that may be on your boat, showers, sinks, heaters and heads for example. Reinstall all the drain plugs you removed. Now is where you need to get a little creative. By visiting your local hardware store you should be able to rig up a bilge pump to attach to your motor flusher. Then drop the bilge pump into a 5 gallon bucket filled with RV antifreeze with a rating of at least –50 degrees. Connect your pump to a 12 volt power source and start the engine. BE CAREFUL! Only run the engine while the bilge pump is feeding the RV antifreeze and shut off immediately when it reaches the bottom of the bucket. Also the RV antifreeze will be exiting the exhaust of your boat, and should be reclaimed either in a bucket or some other device to stop it from leaking on the ground of shop floor. After the engine is shut off, allow to sit for a few minutes, recheck your engine oil level and check for oil leaks. With a can of fogging oil, remove the spark arrestor or air plenum and spray liberally into the carburetor in all venturies. Replace the air plenum or spark arrestor. Remove the spark plugs and liberally spray fogging oil into the cylinders and replace the spark plug into the cylinder head. It may be easier to remove one spark plug at a time to insure the wires go back on in the same order as they came off. This is also a good time to inspect the condition of your spark plugs, they should have a chocolate brown electrode. Any other color of build up on your spark plug could indicate problems, and signal the need to take into a professional service center. Now disable the boat, so it will not start, which can be as easy as switching the emergency kill switch to “off”. Now crank the engine for about 30-45 seconds and shut the switch off. Now that the fogging oil has coated the internal portion of the engine, apply fogging oil to a shop rag and wipe down the exterior of the engine. This helps from corrosion build up on your engine. Now disconnect the battery, always removing the negative side first. A battery has the best chance of surviving the winter if it stored in a warm dry environment, but sometimes that is not an option. If your boat is an inboard, check the transmission oil level and condition and make sure if equipped the transmission drain has been removed and reinstalled. Now your inboard is ready for storage. If you have an inboard/outboard (sterndrive) or an outboard you have some more work to do. On the sterndrive unit or lower gearcase on an outboard remove the bottom drain plug and place an oil pan underneath to catch the oil. Now remove the upper fill plug and vent plug if it has one. On some models, you’ll need to remove the gear lube bottle fill cap located on the engine. Pay close attention to condition of the oil, if it is milky water has contaminated the system and the gearcase mat need resealed. If it has metal shavings or flakes, it may indicate gear failure and should be taken to a professional service center. Now refill the gearcase with the recommended oil as prescribed in your service manual, our gear lube selection is here. Your application may require an oil pump to fill the gearcase. IMPORTANT fill the gearcase from the bottom grain plug up to the fill level. Air can become trapped if it is filled from the top down! Reinstall the bottom drain plug and the upper fill plug and vent plug, or fill bottle cap. Now remove the propeller and inspect the propeller shaft seal, it is not uncommon to find fishing line wrapped around here and if caught soon enough it will save a costly repair. Lube the propeller shaft with spline grease. If needed, now would be the ideal time to have your propeller repaired or tuned up. Before storage it is a good idea to clean the outside and inside (including bilge) as it will be easier to remove a lot of the contamination before it dries on all winter.

Please keep in mind this is a recommendation of procedures from BargainBoatParts.com and in no way is it meant as a replacement for your specific models service manual. BargainBoatParts.com will not held responsible if these procedures are followed and failure still occurs, as all models and applications can be different.

Hope to see you all next year for more Happy and Safe Boating!