How to Change Yamaha F225 Lower Unit Oil

Neglecting to change the lube in a Yamaha outboard’s lower unit can lead to some unnecessary chaos. Even a small amount of water mixed in with the gearcase oil can wreak havoc inside the lower unit. 

Every outboard’s lower unit oil should be changed once after every 100 hours of use, or when storing the engine. Watch the video above and follow the steps below to change the lower unit oil in a Yamaha F225TXRC outboard.

NOTE: We worked on a Yamaha F225, but the process is the same or similar on most outboard makes and models.

Tools and Supplies – Yamaha F225 Gearcase Oil Change

• Flathead screwdriver
• Drain pan
• Oil pump
• Marine gearcase oil (2 quarts)

Changing Yamaha F225 Gearcase Lube

Step 1. Tilt the outboard to about 30-degrees, which puts the lower unit at an optimum angle draining the oil.

Step 2. Remove the oil vent screw and washer from the top right side of the lower unit. Next, inspect the washer for wear and replace it if necessary.

Step 3. Put a drain pan under the lower unit, and remove the oil drain/fill screw and washer from the bottom of the gearcase. Inspect the washer for wear and replace it if necessary.

PRO TIP: You should replace the vent screw and drain/fill screw washers after every few oil changes, regardless of what condition they’re in.

Step 4. Drain out the old gearcase lube, then tilt the engine back down to the vertical position after the oil has drained out.

Step 5. Attach an oil pump into a container of marine gearcase oil and slowly pump the new oil into the lower unit. Continue to add oil until it begins to overflow from the vent hole at the top of the lower unit.

Step 6. Reinstall the vent screw and washer, then remove the oil pump adapter and reinstall the drain/fill screw and washer.

Step 7. Clean off any excess oil from the lower unit using contact/brake cleaner and you’re done. 

Ready to change the engine oil next? Watch the video below to see how to change the oil in a Yamaha F225 outboard.