Any body have this happen on a 660

[xxl]

Any body have brown spot in front of there muffler on. A 660. ? Engine is running 12.8k. The only work done was the ports smoothed

 

[Burning man]

The times I've seen that it was related to the exhaust leaking where the muffler halves meet.

 

[Mad Professor]

Oil that got cooked on?

 

[xxl]

i ll try a new gasket

 

[Burning man]

i ll try a new gasket

Make sure both halves aren't bent.

 

[Burning man]

Oil that got cooked on?

That's possible, the new 391 we have at work has a spot like that now next to the exhaust outlet.

 

[sven556]

Seen it on multiple saws. Doesn't seen to be a big issue.

 

[Dennisthemenace]

Minor exhaust leaks or maybe running a bit rich I'd reckon