84 50hp Mercury 4 cylinder rear water jacket cover leak

7920hpMercury

Petty Officer 2nd Class
Joined
Mar 13, 2009
Messages
111
I have got an 84 50hp 4 cylinder Mercury that is in excellent condition except for a water leak around the #1 top cylinder spark plug hole.

Pulled the power head, got the rear water jacket cover (or cylinder block cover as Mercury calls it) off and discovered the cause of the water leak. Fair amount of corrosion on the block side around the spark plug hole where it mates up to the rear water jacket cover.

I tried a number of different fixes on 20's with this problem, from double gasket thickness to even welding up and filing back flat.

Any suggestions on the best fix for this?

Much thanks!
 

johnjames

Recruit
Joined
Jun 6, 2010
Messages
1
Re: 84 50hp Mercury 4 cylinder rear water jacket cover leak

i have the same problem, i was wondering if you have fixed this...:confused:
 

ugadawg187

Petty Officer 2nd Class
Joined
Aug 18, 2007
Messages
165
Re: 84 50hp Mercury 4 cylinder rear water jacket cover leak

Whoa i just discovered i have this problem yesterday & i was told to replace the water jacket. I have to pull the powerhead to do this?
 
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