melting piston

[rafael]

i have a 235 evinrude which i rebuilt new piston bore over 20 block. rebuilt the carbs new fuel pump engine running great then lost power got home and took the heads off and one piston melted ring are ok electrical ok cpmpression on all piston 120 except the one that melt 95 happened before on piston 6 replaced with a wiesco piston now it's piston number 4 , 3 and 5 look a little melted too even though it got good compression high speed jets ok water temp 145 at all time no restriction i need help driving me crazy

 

[clanton]

Re: melting piston

Depending on year, color of timer harness cover, or timer wires, there is about 3 different timing settings. Most machine shops give the wiesco pistons .002 more clearance the OMC pistons. Check the diode in the power packs, I forget how many marks on flywheel, but mark and checking timing on all cylinders, check for double firing,shine timing light on flywheel nut, the 6 sided nut will appear to have 12 sides if it is double firing.

 

[rafael]

Re: melting piston

the wire harness is all from 1987 stator timing base 1987 stator is a 35 amp was running fine at 4100 rmp for 45 minutes was when i went up to 5500 that it happen