Reuse or replace piston?

[hometheaterman]

The top of the piston looks pitted...you have it apart...so just change everything.

I need to get the piston cleaned up. I can't tell if it's pitted or just carbon caked on. What I can see looks like carbon, but I obviously can't see underneath it.

 

[hometheaterman]

New Engine. There are issues with the balance of your old jug.....

What makes you think this? I'm not 100% opposed to getting a new engine, but I don't see much point in it when it seems like I just need a crank and maybe some rings.

 

[lone wolf]

I can’t tell if the piston is pitted or not. It looks like there is a heavy carbon buildup and the piston below might be fine

Might be Carbon giving the appearance of pitting..

 

[Mad Professor]

Well I'm not a small engine mechanic, but I do credit myself with a fair mechanical aptitude...so my guess would be...and I use the word guess here...is maybe the gap between the fly wheel and the ignition coil may be out of adjustment causing the spark to be a little retarded...possible pre-ignition...or maybe the wrong/rich oil mix...causing carbon build up on the piston, thus hot spots that may be causing the pitting...maybe some food for thought!

Don't look like pitting to me. "pits" look like chunks of built up carbon flaking off

 

[Isidro]

Whatever you end up doing, clearly you should do some replacements while you have your saw apart, add a little more oil in the gas/oil mixture. There will be a break in of about 2 to 3 gas tanks prior to everything "seating" so a little more oil helps with that. Good luck.

 

[grizz55chev]

Just read through this whole thread, Capt Bruce suggested a new engine, and I hate to say it, but it's not a bad idea, given the cost to put the saw back together and cutting wood . If it's a learning experience you're after and time isn't an issue, then Caber rings, crank seals, used oem crank, clean everything and replace all rubber parts, also oem. A carb kit is also recomended. These are dead simple machines,not to many people would bother spending a fortune trying to save it, but once you've done it, and you're happy with the result, you may enjoy the process and move up to a saw that is worthy of the time involved. It's very rewarding taking a thing destined for the landfill and hearing it live again. Either way you go, good luck with it.