I got an old Pioneer P61 that was sitting outside for 10 + years. Decided to see if it would run, it did for a short period but the engine lost power (wound down) and saw lost compression.
Pulled apart and found piston scored (scratched) near exhaust port. Bought a new piston, crank seals and base gasket, honed out scratches in bore, rebuilt the carb. Got saw up and running but after a few minutes it would wind down and shut off. This happened multiple times with this rebuild, very similar to what it did when I first got it. used synthetic oil mixed with gas at 40:1.
Saw did same thing again yesterday only this time it lost compression again. Pulled apart and piston and bore are scored in exactly same locations as the previous piston
Pretty sure mixture was good. Only other thing I noticed is that after running for 2-3 minutes under light load, the fuel in the tank would be bubbling and the fuel line going to the carb looked like it had air mixed in with the fuel. Wondering if this caused it to lean out?
I've seen 2 strokes seize and burn pistons due to bad fuel / oil ratio but this doesn't appear to be that. Only other possibility is maybe the cylinder was warped and when it got hot it started rubbing more on that side of cylinder.
Anyone have an idea what would cause this?
Saw has a 36" bar and I put a new custom made chain on it. Good parts saw if someone is looking for parts. I can't justify spending more money on it.
Pulled apart and found piston scored (scratched) near exhaust port. Bought a new piston, crank seals and base gasket, honed out scratches in bore, rebuilt the carb. Got saw up and running but after a few minutes it would wind down and shut off. This happened multiple times with this rebuild, very similar to what it did when I first got it. used synthetic oil mixed with gas at 40:1.
Saw did same thing again yesterday only this time it lost compression again. Pulled apart and piston and bore are scored in exactly same locations as the previous piston
Pretty sure mixture was good. Only other thing I noticed is that after running for 2-3 minutes under light load, the fuel in the tank would be bubbling and the fuel line going to the carb looked like it had air mixed in with the fuel. Wondering if this caused it to lean out?
I've seen 2 strokes seize and burn pistons due to bad fuel / oil ratio but this doesn't appear to be that. Only other possibility is maybe the cylinder was warped and when it got hot it started rubbing more on that side of cylinder.
Anyone have an idea what would cause this?
Saw has a 36" bar and I put a new custom made chain on it. Good parts saw if someone is looking for parts. I can't justify spending more money on it.
