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346xp with scored piston

Post in 'The Gear' started by mikefrommaine, Mar 18, 2013.

  1. I just picked up this 346xp. Owner said it may have been straight gassed by someone he loaned the saw to. It sounded ok to me but I had never run one before.

    I got it home and tested the compression. 150 psi after the saw was warmed up. The spark plug was very fouled so I put a new one in and tested the saw. It cuts fine with plenty of power. But I only ran it for a few cuts.

    Before I sold it to someone else I figured I should pull the muffler. Of course one of the muffler bolts stripped out. But I got it off and this is what I found. The scoring is very light and goes down about 1/3 of the piston. The pic actually makes it look worse then in person.

    I poked around at the rubber bits and they all seem to be in good shape. I know I need to pressure test the saw.

    If it passes the pressure test would you run the saw as is? I don't want to sell someone a problem so I might keep it for myself. If the saw had been straight gassed will the scoring continue to get worse or will it stay the same?

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  2. MasterMech

    MasterMech Guest

    I'd try top clean that cylinder up with acid and get a new piston for it. Lots of good aftermarket slugs for not a lot of $$.

    That saw looks to need a bath too. All that crud isn't helping that saw run any cooler,

    I wouldn't sell a saw that I knew was damaged unless it was for parts or with full disclosure. ::P
    BobUrban and Thistle like this.
  3. I wouldn't sell it as is, but if I keep it for myself any reason I can't leave it alone?
  4. And would you use a meteor piston? Or are others ok?
  5. MasterMech

    MasterMech Guest

    Honestly, I use OEM 90% of the time. Meteor is a trusted brand and would be my 1st choice for aftermarket. Others could be hit or miss but I'm just starting to play with some of the aftermarket stuff myself.

    I'd still fix it if it was mine, but that's just me. You could probably get away with leaving it alone but just knowing it was there would bug me. You never know, you might pop that cylinder off and discover it's still clean, and just the piston is whupped.
    BobUrban likes this.
  6. HittinSteel

    HittinSteel Minister of Fire

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    Northeastern Ohio
    If it has 150, I'd probably just run it unless I was looking for a project. In that case I'd get a Meteor piston but use OEM clips. While you have it torn down, I'd measure squish and see if you can get rid of the base gasket.

    Oh yeah, first order of business with a 346 is a muffler mod.
    BobUrban likes this.
  7. Jags

    Jags Moderate Moderator Staff Member

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    Loc:
    Northern IL
    It ain't gonna get any better, that is for sure. I would pull the jug. If it is scored, put it back together and run the thing till it don't run - then replace slug and jug. If it is NOT scored - replace the slug now and save the jug.
    BobUrban likes this.
  8. My buddy stopped by with his 346xp to compare how they sound. Mine is a little louder but his has the green cap meaning it has the catalytic muffler. Otherwise they sound pretty close to the same and have the same amount of power.

    I don't think the average guy would know anything is wrong with the piston by running and listening to it.

    I have a guy coming to look at it tomorrow. I told him about the scoring and he is interested at 250. I only have a 100 and a spark plug in it, kind of hoping he doesn't buy it ;) If he doesn't I'll put a new slug in it and put it into my personal collection and sell the 026 and maybe the 361..

    A ms 200, 346xp, 372xpg and ms 660 might be my new four saw plan. Dont want to be a brand snob.
  9. lukem

    lukem Minister of Fire

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    3,687
    Loc:
    Indiana
    I would personally run it till it pukes then redo the whole top end....if I was planning on keeping it.
  10. I sold it and my 372's today.

    The 346 actually showed 155 compression on his gauge.
  11. MasterMech

    MasterMech Guest

    Everybody's gauge is going to be a lil' different. One shop I knew of scrapped out a lot of engines since they were all reading "low compression". Took 'em awhile to realize the tester was whacked. ;lol
  12. He was measuring it cold. I measured it after it had been warmed up. I guess that could be the difference as well.

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