How to Winterize a 75 HP Yahama Boat Motor

Yamaha motors can be found on all kinds of boats, with different power ratings.

Owning a boat can be a great source of enjoyment for you and your family and friends. You can drive around on the open water, go fishing or entertain your friends for hours. When winter comes, however, many boat owners must store their boat to protect it from the elements. Part of protecting your investment is a process called winterizing. Winterizing a boat yourself can save a lot of money in labor from a marina, and give you a better understanding of how your boat works.

Things You'll Need

• Fuel conditioner and stabilizer
• Fresh gasoline
• Hose
• Fresh water source
• Water flushing hose attachment
• Engine fogging oil
• Medium-sized oil draining container
• Allen key/wrench set
• Replacement gaskets for gear oil drain plug and oil level plug
• SAE gear oil (#90 unless otherwise stated in owner's manual)
• Pressurized gear oil filling device

Instructions

Flushing/Fogging

1. Fill your gas tank with fresh gas and fuel stabilizer before you run it for the last time. The mixture should be about 1 oz. of stabilizer per gallon of gas, but check the directions. Allow the motor to cycle the fresh gas through the system before turning it off. When you take the boat out of the water, be sure to rinse the motor down with fresh water to remove any dirt.

2. Remove the latches and the pull the cowl off the top of the motor. Hook the hose up to the fresh water source and attach the flushing attachment to the boat and the hose. Place the flushing attachment over the cold water intakes on the lower portion of the motor. These look like small slivers along the sides of the motor. Turn on the fresh water source and allow it to begin pumping into the motor. Start up the motor and allow it to run for a few minutes to flush the system.

3. Spray the fogging oil into the intake silencer alternately while the engine is still running. You may also have a fogging hole for the silencer. If that is the case, spray the fogging oil into that hole. The engine should begin to smoke at this point. The motor should nearly stall, signifying that the process is complete. You may now shut the motor off.

4. Remove the flushing attachment, and replace the cowl on the top of the motor. Wipe down the motor to remove any water that could freeze and cause problems.

Lubrication

1. Locate the gear oil drain screw on the lower end of the motor. It should be near the very bottom, and often requires an Allen wrench to unscrew. At the same time, locate the oil level plug on the lower end. If you have trouble finding these, consult your owner's manual under the maintenance section. Once you have located them, tilt the motor until the gear oil drain screw is at the lowest possible point. Lock the motor in place using the tilt lever or knob before working on the lower end.

2. Place the medium-sized container underneath the location of the gear oil drain screw. Remove the gear oil drain screw along with the gasket and allow it to begin draining. Also remove the oil level plug. Allow the gear oil to drain completely before replacing the plugs. Be sure to replace the old gaskets with new ones, as old ones can rupture and leak oil.

3. Adjust the tilt until the motor is completely vertical again. Unlock the support lever before adjusting the tilt. Using the pressurized gear oil filling device, begin injecting the new gear oil into the gear oil drain screw hole at the bottom of the motor. When the new oil begins coming out of the oil level plug hole, reinstall the oil level plug with the new gasket, as well as the gear oil drain plug.

Tips & Warnings

• Normally, when fogging the motor, it will not have to be placed in gear, and can be left idling. If you need to put it in gear, or feel that there is a risk of the propeller spinning, make sure you remove it before you turn the motor on. This will prevent personal injury when working closely with the motor.

• Inspect your old gear oil after replacing it. If it seems milky, you have a leak that is allowing water in. It is very important to have the motor inspected by a properly certified repair facility before running the motor again.

References

• Yamaha: 75hp Outboard Motor Owner's Manual