Adrpk said:
Please don't tell me that. It already has a new pisotn cylinder. I was planning to slab this oak after I buck it so I am using a 38-1 mix. What would score the piston?
I'm not saying its scored, I'm saying since its only a 5 minute job to pull the muffler and have a look. If the piston looks ok that step is out the way. If it is scored you know what the problem is, either way its only a 5 minute process to find out one way or the other.
Heat and too many RPM's will score a piston. A air leak will cause over reving and score a piston no matter if you just replaced the jug/piston yesterday. Carb set too lean will score a piston. There's alot of things that will score piston. Beleive it or not many a dull chain has scored many pistons because of over reving in the cut.
You say you have had the piston/cylinder replaced before but when you had it replaced did the shop or whoever replaced find out why it went kapoot. There is always a reason why they score and if that reason isn't corrected the new piston will fail as well due to the same reason.
Save yourself alot of headache and merely pull the muffler and have a look, you may well see a nice perfect piston in the exhaust port and if so then you can go into the saw further. I'm just saying since it so easy to do go ahead and get that step out the way....