036 QS Piston Wear

[cedarshark]

I thought I would share a couple pics of a piston pulled today from an 036 QS I bought at an estate sale. The saw had been under a workbench in a garage for a while and was pretty nasty. A quick pull on the rope confirmed it had no compression. It took a couple hours of cleaning to reach a point where it could be diassembled.

As you can see, the piston is scored on the exhaust side with a piece of the piston missing from the lower skirt. What I found interesting is the amount of wear to the skirt on the exhaust side.

It appears the chunk of piston was ejected from the cylinder but it is not in the muffler nor the crankcase. The jug cleaned up fine and a new piston is in the mail with new seals.

Question: Do you think the piston scored before or after breaking the piece off the skirt & doI have a mechanical problem elsewhere in the saw (bearings) that caused the excessive wear to that side of the piston?

 

[Big_Wood]

piston scored wearing the skirt thin then skirt broke from piston slap. looks like someone really forced that one to keep going as long as possible during the score event as well.

 

[lone wolf]

Piston slap killed it, sucking dirt will wear them out to that point. You need to Vac / pressure test it and put in seals and a top end anyhow. Replace air filter.

 

[cedarshark]

piston scored wearing the skirt thin then skirt broke from piston slap. looks like someone really forced that one to keep going as long as possible during the score event as well.

There was not a great amount of transfer on the cylinder wall. almost as if the skirt wear happened over a long period of time and got thin enough to finally give in. Looks like the orig piston and cylinder.