Ok, it isn't 3am anymore... what was I thinkin?
yes, post pics asap...that's a good idea. If you are just looking at a piston then that's $40 or so. But the 350 really needs a diagnosis as to what was wrong in the first place. Its likely it has a plastic intake clamp ...and therefore a leak in that spot. That needs to get changed...$10 or so for the part. The base adapter likely needs to be resealed... there sometimes is a leak between the chassis and the base adapter necessitating some machining of the base adapter ...sanding etc to get it flat and then a reseal. This costs nothing but time. new base gasket, air filter, fuel filter, new lines maybe.... it can cost a few $$ for sure. This is probably what it needs at minimum. stage 2 involves machining the base adapter to lower the squish and up the compression...and doing a little port work to open the exhaust and intake and retime the saw optimally.
You can ...if you have the $$... get a new 346xp P&C from spike60 (a member here) and then you'll have a rippin saw, but at quite a cost.
if I might make a suggestion... sell the saw as a parts saw... or better yet part it out...you could make money.
best advice...if you really want a 350 then get one from the trading post that has been thoroughly gone through. someone just sold one for $200.... it had a 44mm P&C ...so it was detuned a bit, but still a completely gone through saw. new old stock 346xp's go for $500 ... and if you wanted to upgrade this 350 to the 346xp P&C you might spend close to 300-400 doing it. you run into the law of diminishing returns quickly.
either way, even if you buy my 350...expect to fiddle with it a bit. they are fun little saws for sure...but they need tinkering. the good news is that they are one of the easiest saws to maintain, tinker with, and buy cheap parts for. best of luck whatever you decide....
-Mattyo
ps... i'll make you this offer.. if you ship the saw to me, at your expense, i'll give a a quote to fix it.... or me to buy it as parts, or something.... if you don't like my quote, i'll ship it back at my expense (but in pieces because it'll be completely apart). not trying to speak for him, but OLD CAT likes to fiddle with these too, and would definitely be qualified to fix this for ya