Mercury Tracker 25EL Water Pump Repair
When the water pump fails on a Mercury outboard, the impeller is usually to blame. Replacing the water pump on a Mercury 25 outboard can be done easily with a complete water pump repair kit.
Watch the video above and follow the steps below to replace the water pump assembly on a Mercury Tracker 25 outboard engine.
NOTE: We worked on a Mercury Tracker 25EL, but the method for repairing the water pump is the same or similar for most outboard motors.
Tools and Parts – Mercury Tracker 25 Water Pump Repair
How to Replace Mercury Tracker 25 Water Pump
To access the water pump, you’ll need to remove the gearcase/lower unit from the outboard. Watch our Mercury Tracker 25 lower unit removal video below for reference.
Step 1. Pry the rubber bushing from the top of the water pump assembly, and remove it by sliding it up and off the driveshaft.
Step 2. Remove the four 10mm bolts from the water pump assembly, followed by the water pump housing.
Step 3. Remove the impeller and the nylon washers above and below it.
Step 4. Remove the woodruff key from the base of the driveshaft, then pry the wear plate and the gasket beneath it from the gearcase and remove them.
Watch the clip below to see the water pump disassembly segment of our Mercury Tracker 25 water pump repair video.
Step 5. Install the new gasket and wear plate (both included in the water pump kit), followed by the nylon washer that goes below the impeller.
Step 6. Install the new woodruff key (included in the water pump kit) using a dab of PTFE marine grease to hold it in place.
Step 7. Install the new impeller and the new nylon washer above it (all included in the water pump kit), and apply a thin film of PTFE marine grease to the plate.
Step 8. Install the new O-ring into the new water pump housing (both included in the water pump kit) and lightly smear the inside of the housing with PTFE marine grease.
Step 9. Install the new water pump housing while rotating the driveshaft clockwise. This ensures the impeller’s blades are turned in the correct direction within the housing.
Step 10. Reinstall the four 10mm water pump assembly bolts.
Step 11. Install the new rubber bushing on top of the water pump housing, and the new water pipe sleeve into the water pump housing (both included in the water pump kit).
Watch the clip below to see the water pump reassembly segment of our Mercury Tracker 25 water pump repair video.
After repairing the water pump, you’ll need to remount the lower unit to the outboard. Watch our Mercury Tracker 25 lower unit reinstall video below to see how it’s done.