97 Johnson 112, blown piston

[Bob Gale]

My 97 Johnson 112 special, ser # G4047539 Model XE112SLEDR has a badly burned #2 piston. The piston is partly melted on the intake side and crown. The other pistons seem normal. What can cause this, timing, fuel problem?
Any suggestions, I don't want it to happen again..

 

[reeldutch]

Re: 97 Johnson 112, blown piston

what plugs are you using?
what rpm range is it propped for.
how is your fuel
octane level

have you lot of carbon deposits?

may be some pics will help.

 

[Bob Gale]

Re: 97 Johnson 112, blown piston

Hi, thanks for responding.
The plugs are Champ QL77JC4
RPM is around 5400
Octane is 87
No carbon deposits
I have pictures but at 4 meg in jpg format they are to big for for this site which has a limit of 96 Kb. If I can figure how to reduce them I'll post.
Bob