water comming out #1 spark plug hole!!!!!

hfd12

Seaman Apprentice
Joined
Jul 10, 2010
Messages
31
I have a 1974 mercury 650 with thunderbolt ignition and i just notice that i have water comming out the #1 cylinder spark plug hole. the boat still starts fine and runs fin on muffs. do i need a head gasket? I have great compression at 125,135,135. thanks
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: water comming out #1 spark plug hole!!!!!

No head gaskets on these engine. What you need is a head cover gasket, and a service manual....

Chris.......
 

DamianJP

Chief Petty Officer
Joined
Mar 25, 2008
Messages
605
Re: water comming out #1 spark plug hole!!!!!

Hey hfd12

Check this thread too for more info.
http://forums.iboats.com/showthread.php?t=420542&highlight=damianJP

Is it a 65HP (650?). Lemme know what HP so I can grab a diagram.

The water by the plug is prolly a water jacket gasket and/or the metal that sandwiches that gasket is pitted and not create a good seal for the gasket.

My friend just did the same job on his 1980 Merc 50HP. Had to pop off the water jacket cover and make sure the cover isnt warped. Then check for pitting on the areas that sandwich the gasket. Then grab a new gasket. If pitting he used JB weld and then lightly sanded it back down to a perfect level again to make up for the pitting so the gasket has backing to create a seal.

Might be just a gasket, but look for pitting while your there.

Some people prefer to try and band aid it with silicone because the pressure should not reach more than 6-8 PSI (low PSI water in general). And for the fact that they are worried about breaking the bolts that hold the jacket on if the bolts are in bad shape due to salty conditions and such.

PBlaster , WD40 or equivalent tight fitting tools and take it slow. If it were me I would just do it %100 and pop the jacket for a fresh gasket and inspection.


Like achris said. This is a water jacket cover only, so a leak here would not budge the compression in combustion chamber.


Lemme know what you find,
DamianJP
 
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