Pre-alpha water pump melted. What to check?

[Campfire]

So I’m doing a full service on the back end of the boat with a bellows/transom kit and gimbal housing rebuild on a free boat I was given. The water pump housing was melted. There were pieces of the impeller missing.

Besides replacing the entire housing assembly, is there anything further I should do with the cooling system? This is my first time working on boats so forgive my improper terminology. There was also some random pieces that were loose when I pulled the lower end off. One was a semicircle with some large spaced holes in it. It was metal (brass?) and didn’t seem to have hinge mounting points or anything. Any guesses? It was sitting in the bottom part of the gimbal housing where the torn bellows was (which is the reason I’m tearing into this thing initially).

thanks

 

[Bt Doctur]

That piece with the holes was most likely the exaust shutters and from the sound of it the motor was run with no water going to it. Best to backflush from the T stat house backwards

 

[Campfire]

Would a garden hose be enough pressure on the back flush?

What would an exhaust shutter have holes in it? Is that to muffle the sound? It sounds like shutters are to keep water from flooding the engine. The oil isn’t chocolate milk. Just normal looking oil.

 

[Bt Doctur]

Your correct but the shutters belong in the exaust pipe not down there

 

[Campfire]

Is is correct to assume that the impeller can go in either way (there’s no “front” or “back”? I have the vanes clocked the same as the old ones.

The new impeller isn’t symmetrical in the housing, The hole it in the housing that appears like it should line up with the hole in the impeller also seems off center.

​​​​​​​Also, it sits proud of the housing, The Seloc and Clymer manuals don’t mention it being proud of the housing. is that normal?

 

[racerone]

Impellers are offset.----They work when the volume between vanes changes.-----It ---" sits proud " ---means nothing.----Post how much it is proud.------ 0,010" or 1/8" proud is what you need to post.

 

[Bt Doctur]

Depends if you a lefty or a righty.
the driveshaft turns clockwise so the impeller tips end up CCW.
A few ways to install one is put the impeller on the shaft first. place the cup on top and turn the shaft CW and push the top cap downward.
Optional method is put the impeller under some hot water ,when softened and holding it in your left hand insert with a CCW rotating action while pushing it into the cup, try to get the impeller keyway facing the larger stud.

When correctly installed you will be able to turn the shaft with some resistance

 

[Campfire]

Impellers are offset.----They work when the volume between vanes changes.-----It ---" sits proud " ---means nothing.----Post how much it is proud.------ 0,010" or 1/8" proud is what you need to post.

Nothing like an 1/8. Just above the lip. I was expecting it to be seated completely inside the housing or at most flush. I was able to get it in easily (twice. First time I put it in reverse). Just used a bit of marine grease and three curse words.

I’m thinking I should replace the water tube and water pocket cover as they are plastic and likely overheated as well. I backflushed every coolant line I could find with a garden hose. I pulled the thermostat housing as well.