How To Winterize An Inboard Boat Motor (Handy Guide)

Winter attacks your house, and whatever is kept outside gets affected. Cars, bikes, and boat engines are most likely to stop working if they get affected by the cold.

Your boat’s engine can freeze, and the freeze damage can cost a lot. However once you get your vehicles or engines winter ready, they will last a long time.

So, let’s see how to winterize an inboard boat motor. With the help of this guide, you can do the winterization all by yourself.

Items you’ll need

Before starting the winterization process, you need to prepare all the materials.

1. The manual for your inboard engine: the manual contains all the technical specifications for the engine, along with the engine cooling system and exhaust. And also the correct procedure for winterizing the boat and the required materials.
2. Water source – you will need to draw water from some water source, such as a water spigot or faucet
3. Water hose – to transport the water to the engine
4. Inboard motor flusher – also called a muff
5. Approximately 5 gallons of antifreez – different types of antifreeze are available but always go for the non-toxic one. You can go for propylene glycol; it is non-toxic and less harmful.
6. Container for the antifreeze – such as five gallon bucket, found at most hardware stores (such as Home Depot)
7. Fogging oil spray – fogging oil works as a protector for your carburetor and engine cylinder against corrosion. It will help your boat run smoothly when you start the boat after winter.
8. Screwdriver – to dissassemble various parts during the winterizing process
9. Fuel stabilizer – essential if your boat runs on gasoline. It prevents water from entering the tank and keeps the fuel frost free. It also helps the boat store for more than six months.
10. You will also need some covers to cover the different parts of the boat.
11. And lastly, transmission oil and engine oil filter.

How to winterize an inboard boat motor (Step by step guide)

1. Focus On Your Boat’s Manual. Winterizing your boat is an important process that will help protect it from the harsh conditions of winter. Make sure to follow all instructions in your boat and engine manuals to ensure a successful winterization. In particular, pay close attention to any special instructions that could be unique to your boat or engine. Improper winterization can lead to serious damage, so it is important to be careful and follow all directions. When using materials for winterization, such as muffs, be sure to carefully read and follow all instructions. Although they are simple and easy to use, improper use of muffs/loss of water to the engine intake can cause significant problems for your boat engine. Take care to avoid any costly mistakes.
2. Fill your tank with gas. Keeping the tank full will reduce the air pressure. Air holds moisture. With a dropping temperature, the moisture will end up as water in the bottom of the tank.
3. Add fuel stabilizer to the tank. Look on the container it comes in to determine the right amount of stabilizer, based on the amount of gas in the tank. It will help prevent varnish build-up in fuel lines and ensure your engine starts up right away after sitting dormant all winter.
4. Warm your boat’s engine/run water through it: Warming your engine also circulates the fuel and stabilizer, making them more effective in protecting fuel delivery system components. To attach your motor flusher or muff, first secure one end of the water hose to a water source. Next, take the other end of the hose and attach it to the water intake on your boat. Make sure that the connection is snug and firm – any loss of water due to a loose connection will damage your engine.
5. Before turning on the engine, confirm that water is running through the muff. Once you have confirmed that there is a water supply, you can start the engine. Once the engine warms up, the coolant will circulate through the entire engine. Also, when we warm up the engine, it helps the fuel stabilizer circulate through all fuel lines. Keep an eye on both the RPM and temperature as the engine runs. It is important to keep the engine at or below 1500 RPM. Demanding more water by running at a higher RPM could result in a lack of water supply. As for temperature, let it reach the level that is typical when running your boat on open water. After your target temperature has been reached, turn off the engine followed by the water supply.
6. Drain all liquid from your boat’s engine. When draining the engine block, be sure to follow your boat manufacturer’s specifications. Once the coolant has been drained, add propylene glycol antifreeze.
7. Fogging Oil and Antifreeze time: It’s important to use a different hose for the antifreeze when winterizing your inboard motor. The one you used earlier will still have water in it, and you want to keep water out of the engine at this point. This will prevent water from getting into the engine. To do this, set up a hose from the muffs to the 5 gallon bucket of antifreeze. 5 gallons of non-toxic antifreeze should be enough for your engine, but if you have any extra plumbing, you’ll need to add antifreeze to those as well. Now, connect a hose from your muffs to the container of antifreeze. This will allow the intake to pick up the antifreeze instead of water.
8. Once everything is in place, turn on the engine again. Let it run until you see antifreeze flowing out of the boat’s exhaust. When you see that happening, let it run for about 20 more seconds.
9. To fog your engine, start by removing the carburetor cover and spraying fogging oil into the carburetor. Continue spraying until the engine stalls. The fogging oil will form a protective coat on the carburetor, preventing rust.
10. Once complete, remember to turn off the engine and detach the muffler from the boat.
11. Before finishing, you must check the exhaust system for any carbon build-up or corrosion. Remove the raw water injection hose from the injection nipple; check to see if it is blocked by debris.
12. Inspect all hoses if there is some softness, bulging, or cracking. Make sure all hose clamps are tight.
13. Seal all the openings which go into the engine so that damp air does not go inside. Use plastic containers and tape can cover the air inlet, transmission, crankcase breathers, and exhaust outlets.
14. You can write on a piece of paper how many caps you have put on so that you remember to take them off.
15. Check the motor mounts and their flexible rubber elements for softening caused by oil leaks.
16. Lube all the grease points on the engine.

Conclusion

Winterizing your inboard boat’s engine is very important; it helps the boat to run smoothly after storing for a long time. If not winterized, then the engine can get damaged, (e.g. ice blocks could form inside the fuel tank).

It may look like there are too many steps to follow, but if you follow these steps correctly, then you will be able to winterize the boat engine nicely.

If you still find it difficult to understand, be sure to follow the manual provided with the boat. The process will become easy if you follow the instructions specific to your watercraft. Also Read >>>