How to Replace a Water Pump on a Mercury 40 | Mercury 40HP 2- Stroke Water Pump Replacement

How to Replace a Water Pump on a Mercury 40 | Mercury 40HP 2- Stroke Water Pump Replacement

Get your Mercury 40 2-stroke water pump repair kit here:

See how to change the water pump on a 2-stroke Mercury 40 HP outboard in this video from We’ve already removed the lower unit from the powerhead, and if you need to see how to do that you can find it here:

Mercury 40 2-Stroke lower unit removal:

John is using a kit here that includes all of the parts you need. We’ll start by removing the four bolts that hold the water pump cover in place, and then we’ll get the old water pump impeller removed. Then we’ll replace the pump. Because the initial start up will be dry, we’ll put a little marie grease on the housing and the wear plate. Get the grease here:

See this diagram for a better look at the Mercury 40 2-stroke water pump and how it fits onto the lower unit:

Removing the old water pump – 0:50
Installing the new water pump – 1:40

Find Mercury outboard parts here:

Talk to us:

In the video we’re working with a 2002 Mercury 40 HP 2-stroke outboard motor, but you may have similar steps for your Mercury outboard. If you’re not sure whether these steps apply to your motor, leave a comment and we’ll get back to you.


Mercury 40HP 2-stroke output shaft seals:

Mercury 40HP gearcase lube change:



Norberto Clemente says:

Perfectas imágenes.
Me gustaría ver reparacion kit bomba de gasolina mercury 50cv 2 tiempos año 1999

Brent HUbbard says:

I have a 2007 df225 Suzuki With water in the engine oil. I flushed it with new oil and filter and still brownish color. I’ve read so far it’s an internal problem. Maybe a head gasket or worse crakes head. One thing I’ve done that was wrong was running the engine while water was on the flush port. Could this have been where I screwed up? Thanks

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