I have a 1972 mercury 80 hp outboard. I rebuilt it last year by replacing all the piston and rings. I tried to change the head gasket and exhaust gaskets but the bolts were badly oxidated. I broke one bolt on the exhaust side. Now the botton cylinder is wet all the time. Dont think its fuel because I swopped the carbs. Do i need to replace the exhaust gasket. If so what would be the best way to get the bolts out. Heat might ruin the head. Tried PB baster but didnt help.
The cylinder head on that motor is non-removeable. What appears to be the head bolts is actually a water jacket cover over the head.
Water will enter the bottom cylinder via the lower crankcase seal, the inner exhaust cover, or the exhaust baffle. You will need to pull the powerhead to replace the crankcase seals (install 3 seals vs the two it came with). It is a lot easier to pull the powerhead to get the the exhaust water jacket
Thanks. Whats the best way to get oxidated bolts out of the exhaust cover. I got most of them out but 4 wont budge. I broke 1. Afraid to heatup might riun aluminum block. Any other suggestions. The bolts that came out were full of white powder.
There is no "good" way to remove broken bolts.......Some of the methods I use are.
1. Lots of PB Blaster everyday for a week
2. Center punch, and drill it out
3. A Dremel with an end mill type bit.
4. heat, of course
5. Air impact.. carefully
6. Easy-outs
Here is a link that might help you out
Mercury outboard bottom cylinder wet.
Re: Mercury outboard bottom cylinder wet.
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