Mercury 200 Verado Water Pump & Impeller Replacement
An overheating outboard or an usually weak stream of water coming from the tell-tale are sure signs of a failing impeller or water pump.
Usually the impeller is the culprit, but you won’t know until you remove the lower unit and take a look. Whenever you have to remove the lower unit from your outboard, it’s worth replacing the impeller, driveshaft and shift shaft oil seals in one go. Follow the steps below and watch the video above to learn how to replace the impeller and repair the water pump on a Mercury 200HP outboard.
NOTE: We used a Mercury 200XL Verado, but the process is the same or similar for most outboard motors.
Tools and Parts Needed – Mercury Verado 200 Water Pump Repair
NOTE: Before you can replace the shift shaft seals, you must remove the lower unit from the outboard. Watch the video below to see how to remove the lower unit on a Mercury 200.
How to Remove a Mercury 200XL Verado Water Pump & Impeller
Step 1. Remove the four 10mm bolts securing the water pump housing, then remove the housing by sliding it up and off the driveshaft.
Step 2. Remove the impeller and the woodruff key securing it against the driveshaft.
NOTE: The impeller may come off with the water pump housing or may remain on the driveshaft. Slide it off If it’s still on the driveshaft. Pull it out if it’s in the water pump housing.
Step 3. Remove the metal plate that was beneath the water pump housing and the impeller.
Watch the clip below to see the water pump and impeller removal segment of our Mercury 200XL Verado water pump and impeller repair video.
Inspecting the Water Pump & Impeller
Step 4. Inspect the impeller for broken or missing blades.
NOTE: If any pieces of the impeller are missing, they’re somewhere in the outboard’s cooling system and must be removed before they cause a blockage in the system. You’ll have to flush the cooling system to extract all the missing impeller pieces.
Step 5. Inspect the inside of the water pump housing for signs of wear.
NOTE: The housing has a longer lifespan than the impeller, so it’s more likely that the impeller will need replacing but the housing won’t. However, any mechanical part will eventually become worn, so if you see any wear inside the housing, it’s time to replace it.
Watch the clip below to see the water pump and impeller inspection segment of our Mercury 200XL Verado water pump and impeller repair video.
How to Reinstall a Mercury 200XL Verado Water Pump & Impeller
Step 6. Install the lower gasket onto the lower unit.
Step 7. Install the metal plate, and smear a thin film of grease around the center of the plate where the impeller will sit.
Step 8. Install the upper gasket, making sure the grey surface is facing upward.
Step 9. Install the woodruff key into the drive shaft. Put a dab of grease on the woodruff key to prevent it from falling out of its channel in the driveshaft.
Step 10. Install the impeller over the driveshaft and onto the woodruff key.
Watch the clip below to see the impeller installation segment of our Mercury 200XL Verado water pump and impeller repair video.
Step 11. Smear a thin film of grease inside the water pump housing, and install the housing over the driveshaft and the impeller. Rotate the driveshaft clockwise as you push the housing over the impeller to ensure the impeller’s blades are in the correct direction within the housing.
Step 12. Reinstall the four 10mm bolts securing the water pump housing and tighten them down.
Step 13. Install the water pump housing seal over the driveshaft and into the housing. Use the plastic tool (included in the impeller and water pump kits) to set the seal at the correct height by pressing down on it until the tool bottoms out against the water pump housing.
Step 14. If you bought the impeller repair kit, replace the O-rings within the tube that connects the water pump housing and the mid-section of the outboard. The tube has an arrow denoting which way to install it. The orange O-ring should be installed in the lower end of the tube, and the black O-ring installed in the upper end. Lightly grease both the O-rings.
NOTE: These O-rings are not included with the water pump repair kit.
Watch the clip below to see the water pump installation segment of our Mercury 200XL Verado water pump and impeller repair video.
Having replaced the impeller and repaired the water pump, it’s time to reinstall the lower unit onto the outboard.
Watch the video above to see how to do a Mercury 200XL Verado lower unit installation.