What caused this to melt?

[K-Dawg]

Come off a motor I burnt number 6 in. But, this is number 2 and it looks fine. Did a lean condition cause this?

[myron]

what does the top of the piston look like? From what I see it looks like detonation

[K-Dawg]

It looks fine. I even looked the head gasket over good. That melted part is by the exhaust port.

[chad202]

looks like a gasket leak to me.

[imq707s]

looks like a gasket leak to me.

Yep....that's what I was thinking.....

[Jay Smith]

Could be that head made a dip there and had a leak like the others said, I've found big issues with some of the Mercury castings.. You cut and a small pin hole appears then the farther you cut the bigger the cavity becomes in the casting..

Jay

[r.c.]

I.M.O. the sealing ring would have been burned if the gasket was leaking. leaning out can be a factor that going unsaid. it can be caused by heat saturation. an irregular surface where the heat saturates in the pores or chatter marks, bad castings. etc.

[Tom Foley]

I had a situation where a leaking head gasket ( water Leak ) caused cavitation burn from the boiling water (freshwater ) on the head , not as bad as that but similar .

[Steve Pope]

Can you show us the head gasket, both sides. Popey

[K-Dawg]

Already trashed the head gasket. It had no damage. It looked fine.