2101XP Carbon scoring?

[altatim]

I recently got this 2101 and runs/cuts fine. Pulled the muffler and it has this small area thats scored. I haven't pulled the cylinder but from the spark plug hole it looks like one small line on the cylinder that I can barely feel with a probe. The piston feels smooth but once again I can barely feel the scoring. Worth putting a new piston in it? No lean issues but I'm unfamiliar with this saw and I don't really want to wreck it. 125psi compression, starts very easily.

 

[singinwoodwackr]

Should all clean up fine. Just re-ring. But, before restarting you need to find the cause. Or, you’ll just repeat in a short time.

 

[NSEric]

I skip the vac/pressure testing some on here do and just put new seals and gaskets in old saws. Once they're over 20 years old, the seals can go anytime from dry rot.
I'd put crank seals, intake gaskets, base gasket and a new piston/ring in the it after I cleaned the tiny bit of scoring up in the cylinder.

 

[singinwoodwackr]

I skip the vac/pressure testing some on here do and just put new seals and gaskets in old saws. Once they're over 20 years old, the seals can go anytime from dry rot.
I'd put crank seals, intake gaskets, base gasket and a new piston/ring in the it after I cleaned the tiny bit of scoring up in the cylinder.

Good luck

 

[bwalker]

I bet you have an air leak. If you don't fix it the scoring will just get worse.

 

[Bob Hedgecutter]

Dunno- looks like it could be heat related to me- big saw, big bar, dull chain pushed hard will heat that quadrant.
But peeking through the exhaust port gives an indication and then we can all play the guessing game......

Pop the top off it and inspect the exposed piston- rings could be stuck- piston could be smeared just around the corner from the port, bit of bottom end bearing may have come out and finger ported the cylinder for you- don't know till ya look inside.

 

[altatim]

Should all clean up fine. Just re-ring. But, before restarting you need to find the cause. Or, you’ll just repeat in a short time.

Going to vac test it, just already felt play on the crank and it feels ok, was in use by PO when purchased and didn't surge when turned on its side (both flywheel and clutch) but I still was going to replace the seals for peace of mind. The 125PSI comp was what led me to tear it down.

 

[altatim]

Dunno- looks like it could be heat related to me- big saw, big bar, dull chain pushed hard will heat that quadrant.
But peeking through the exhaust port gives an indication and then we can all play the guessing game......

Pop the top off it and inspect the exposed piston- rings could be stuck- piston could be smeared just around the corner from the port, bit of bottom end bearing may have come out and finger ported the cylinder for you- don't know till ya look inside.

Yep, going to dig into it more. Just was wondering what people though as the marking is not really visible in the cylinder and it isn't scored near the top of the piston.

 

[Bob Hedgecutter]

Going to vac test it, just already felt play on the crank and it feels ok, was in use by PO when purchased and didn't surge when turned on its side (both flywheel and clutch) but I still was going to replace the seals for peace of mind. The 125PSI comp was what led me to tear it down.

Already felt for play in the crank? Main bearings can "feel" fine doing that, but with the cylinder still on you have no idea what the bottom end rod bearing is doing.
I have a 2100 crank here somewhere took out the original top end and then a replacement top end before the previous owner sold it to me- bits of the bottom rod bearing cage were coming apart, looping the case and exiting transfer ports to take a ride between bore and piston- gets expensive- fast.

 

[altatim]

Already felt for play in the crank? Main bearings can "feel" fine doing that, but with the cylinder still on you have no idea what the bottom end rod bearing is doing.
I have a 2100 crank here somewhere took out the original top end and then a replacement top end before the previous owner sold it to me- bits of the bottom rod bearing cage were coming apart, looping the case and exiting transfer ports to take a ride between bore and piston- gets expensive- fast.

Don't worry, I plan on pulling it down, just havent done a vac test and don't want to take off the cylinder until I do.

 

[altatim]

P&V test went fine, pulled off the cylinder and realized the case was full of fuel... so need to do the vac test again lol. Checked the crank and rod and it feels good. No up and down in either but the rod has about 0.050" side to side at the top. Ring gap is 0.014", Cylinder is 2.206", piston is 2.199". There was some superficial "scoring" on the cylinder but a bit of 600grit with soap and water took it mostly away. You could barely feel it before sanding and not at all after sanding for maybe a total of 10 minutes (but that was the whole cylinder so idk). Looks like PO wasn't 100% truthful and straight gassed it....