Water leak at front bolt "weep" hole after water pump replacement

decgaryboat

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Joined
Jul 8, 2025
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2
5th time replacing water pump on my mercruiser 120 alpha. After reattaching L/U halves, considerable water now leaks from the hole in front of the FRONT bolt connecting U/L units.water also streams out from the weep hole at bottom of unit...The bolt with a washer screwed in with a Phillips screw.

The water pump does pump water to engine, and it does not overheat....plus boat shifts fine F, R,N. But, I never remember such a major leak. The exhaust bellows IS badly torn, but I thought that it had nothing to do with cooling system...only with venting/noise reduction. Last point: This was the FIRST startup of the year...so, consider that as well.

Thought id get some ideas B4 I drop the lower unit again to investigate.
 
Joined
Mar 27, 2010
Messages
3,020
If your referring to the small hole noted in the photo I have attached as "drain hole" that's normal. It drains water that leaks into the hollow cavity of the lower half of the drive around the shift shaft. They can get clogged with crud. Did you clean out that cavity around the shift shaft while it was apart?

quad o-ring noted.JPG
 

decgaryboat

Recruit
Joined
Jul 8, 2025
Messages
2
I did not inspect the cavity around the shift shaft. That area usually is water free, isn't it? ...but it is directly below where upper half leak is.
 

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