Water pump issue, I’m at a loss!

I have a 97 Evinrude E40tleuc 40hp motor that is not pumping water what so ever. I changed the impeller, that didn’t work. I changed the Thermostat, it was so corroded I had to break the housing out to remove it. I thought that was the fix, but nope. I then pulled the lower unit back off, and blew compressed air thru the water line, and checked the impeller for the right direction. Nothing! I then pulled the water case off the side of the engine, blew it out and still nothing. The last and final try was reverse flushing through the thermostat opening and that didn’t help anything either.

So what could be wrong? The only thing I haven’t tried is putting the motor in a barrel and seeing what happens. Could it be that there is nothing wrong with the water pump, it just won’t prime with ear muffs on?

I’ve scoured the internet until my eyes hurt. Thanks in advance for your help!


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I have found smaller motors don’t do well with the muffs. Usually 25 and down. While I have no experience with 40 and up, I would definitely try a barrel or back it down a launch before tearing into it again.


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Is the little key under the impeller?

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Little key is under the impeller.


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Put it in a tank and it still didn’t work. So I pulled the lower unit back off, and guess what? The key was missing! I know I put it back when I changed the impeller, but it’s no where to be found. Guess a grimlin got it. Off to the marina I go.


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Always a relief when it turns out to be a simple fix. Easy on the wallet too.

I wonder where the original key went?

Who knows. I know for a fact it was on there when I installed it. Pumps water like a champ now. I’m gonna soak the carbs then I should be good to go.


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You know I didn’t put grease on it though, I bet it fell out while trying to install. Grease is a must...I’m proof.


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Shmelton said:

Grease is a must...

Click to expand...

Grease is your friend!

If you need to, use tape to hold the exhaust gasket in place, get a few bolts holding LU, then carefully remove the tape,