89 135 HP Merc melted piston

[Captn Dave]

A friend's engine seized up and he removed the head and found the lower piston melted.<br />He is planning on rebuilding the engine but I told him he also needs to find the cause of the melted piston.<br />One mechanic told him bad gas?<br />Is this right? <br />What else should he look for?

 

[WillyBWright]

Re: 89 135 HP Merc melted piston

Certainly. It died from detonation. Octane and timing are the usual culprits. Lean conditions can also cause it. An overhaul should include careful timing, carb rebuilds, fuel pump rebuild, water pump rebuild. And FRESH gas.

 

[Captn Dave]

Re: 89 135 HP Merc melted piston

Thanks Willy.

 

[Captn Dave]

Re: 89 135 HP Merc melted piston

Thanks Willy.