My Pre-84 80hp on the weekend would not turn on the flywheel, it was siezed. Managed to free it and started the motor by removing No.1 plug. While running on three of the four cylinders I noticed a vapour pumping out of the plug hole, putting my hand over it and found it to be rusty water.So somewhere water was getting into the bore, removed the top water jacket plate and then could see the problem. Around all four plug castings at the top of the cylinders were badly eaten away by corrosion and on No. 1 cylinder was a small hole which where the water was getting into the bore and rusting. Do these engines have any Zinc anodes for anti corrosion.My question is there any method of a temporary repair till the end of the season. I've used metal epoxy known as K-poxy k-150 for repairing various engineering parts, would this or something similar be any good in the repair. As the engine stays pretty cool under power. Otherwise it means scrapping the Motor, as a new power head would cost more than whats its worth.
dartboy, Usually the corrosion "eats" a hole in the inner water jacket cover, versus the block. if this is the case, the cover can be replaced. You can also epoxy the hole for a temporaty fix. I used Marine-Tex to repair one of mine. It should work until another section of the cover rusts through, or enough corrosion forms to allow the epoxy to fall off.
Thanks for your reply Chris.The corrosion hole is from water jacket area at the top of power head along side the spark plug hole surrounding the cylinder into the bore above the piston. It is not in the jacket cover plate covering all spark plug threaded areas held by 3/16" bolts to the power head.
Dartboy, Although I could not understand your description, there are two covers that seperate cooling water from the cylinder exhaust ports. Marine-Tex should hold for a while, if the area surronding the hole is sound. Make sure you clean the area throughly and wipe with acetone or lacquer thinner, before you apply the marine-tex.
Mercury 80hp powerhead corrosion
Managed to free it and started the motor by removing No.1 plug. While running on three of the four cylinders I noticed a vapour pumping out of the plug hole, putting my hand over it and found it to be rusty water.
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