Mercury Tracker 25 Gearcase Oil Change
When was the last time you changed your outboard’s gearcase lube? Manufacturers recommend the lower unit oil of an outboard be changed after every 100 hours of use or once a year.
Watch the video above or follow the steps below to change the gearcase oil in a Mercury Tracker 25 outboard.
NOTE: The steps to change the lower unit oil on a Mercury Tracker 25 are the same or similar for almost all outboard makes and models.
Tools and Parts – Mercury Tracker 25 Gearcase Oil Change
- Flathead screwdriver
- Contact/brake cleaner
- Drain pan
- Mercury gear lube pump
- Mercury gear lube
PRO TIP: The OEM Mercury brand gear lube pump comes with the correct attachment for Mercury outboards, so you won’t have to buy an additional adapter.
How to Change Mercury Tracker 25 Gearcase Oil
Step 1. Remove the vent screw and washer from the top right side of the lower unit.
Step 2. Position a drain pan under the lower unit, and remove the drain/fill screw and washer from the bottom right side of the lower unit. Let the gearcase oil drain out.
NOTE: You should inspect the vent screw washer and the drain/fill screw washer for wear, and replace them if necessary. To ensure there are no oil leaks, the washers should be replaced every couple of lower unit oil changes, regardless of their condition.
Step 3. Attach a Mercury gear lube pump to a quart bottle of Mercury SAE90 gear lube, then attach the other end of the pump to the drain/fill hole in the lower unit.
Step 4. Slowly pump the new gear lube into the lower unit until it starts to flow out from the vent hole.
Step 5. Reinstall the vent screw and washer into the lower unit.
Step 6. Remove the gear lube pump, and quickly reinstall the drain/fill screw and washer into the lower unit.
Step 7. Clean off any spilled oil from the lower unit using contact/brake cleaner and you’re done.
Watch the video below to learn how to do a gearcase pressure test on a Mercury Tracker 25 outboard.
