[kkilloy]

Just bought a used 1991 15hp Mercury 2 stroke. Ran well at higher speed but would not idle. While running at higher speed engine suddenly stopped. Not locked up, but would not start. Compression test (cold) showed 30 on top cylinder and 90 on the bottom. I disassembled the engine and there is damage to the top piston, rings and light scratches on the top cylinder wall. I believe that the bottom left reed was rusted from sitting for a long period of time and was sucked into the top clylinder and caused the damage. The engine ran very strong before this happened and is in excellent overall condition. I have bought (1) new piston and rings for both pistons as well as new reeds. My question is: Is it ok to hone the cylinder walls to fix this amount of damage? I hope the pictures help!

Thanks,

Kevin

[Laddies]

No problem with honing just try to stay within skirt clearances and you don't have to do anything to a mark below the bottom of the top port edge.

[kkilloy]

I honed the cylinder walls on both cylinders using a brake cylinder hone. It got rid of all but one small scratch. I finished putting everything together and ran it today. It ran and idled great. I am breaking in right now because both pistons have new rings and I want them to seat properly. Checked compression and both cylinder read 90 after three pulls of the pull starter. I am thrilled with the way it is running so far.

Thanks,

Kevin