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  1. #1

    Join Date
    Sep 2019
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    Troy-Bilt

    troybilt trimmer motor bolt broke

    I was using my TB22EC trimmer and it quit. It's the "Trimmer Plus" model and I was using it with the hedge trimmer attachment. The plastic air filter cover has been loose for a while and i noticed it had fallen off. Putting it back on, I tried to start it using the battery jumper thing. It seemed to kick a couple times and it sounded like it backfired.

    It had a good spark and I figured the carburetor was the problem, which is usually the issue with these small engines. Fuel lines and filter were clear. Cleaning the carb didn't do anything so I put a new one on. Still noting. On further inspection, I noticed "something" like a string, sticking out of the side of the engine. It was the "O" ring between cylinder and crankcase. One of the two bolts holding it together was broken. In retrospect, I think the "kick and backfire" broke the bolt after I gave it a shot of ether starting spray.

    Long story short, I finally got the clutch off to remove the plastic shroud, allowing me to get the broken bolt off. (didn't have to drill, etc). Just used a vice grip to grab the bolt and remove. Have new "O" ring and bolts and ready to put it back together. Holding the piston and cylinder "something" fell out. It is a round piece of metal about the size of a hearing aid battery. Didn't know what it was at first, then found that it fits in the side of the piston and covers the piston pin. However, there is only one of these. Perhaps I dropped the other side. Should there be one on each side?

    Lastly, if I'm missing one and can't find it, how can I get a replacement part?

  2. #2
    dougand3's Avatar
    Join Date
    Mar 2012
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    50
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    Alabama
    Mower
    Craftsman

    Re: troybilt trimmer motor bolt broke

    Sounds like a circlip - keeps piston pin thru the rod bearing and on both sides of the piston. Piston may have a collar on one side, so only 1 circlip. Maybe it's a button circlip. Some guessing here because I've never been this deep in an MTD powerhead. IPL is no help - they don't part below a whole short block. https://www.partstree.com/models/tb-...ne-assembly-0/
    89 Craftsman GT18 44", 4 push mowers, Lotsa chainsaws.

  3. #3

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    Sep 2019
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    Troy-Bilt

    Re: troybilt trimmer motor bolt broke

    Quote Originally Posted by dougand3 View Post
    Sounds like a circlip - keeps piston pin thru the rod bearing and on both sides of the piston. Piston may have a collar on one side, so only 1 circlip. Maybe it's a button circlip. Some guessing here because I've never been this deep in an MTD powerhead. IPL is no help - they don't part below a whole short block. https://www.partstree.com/models/tb-...ne-assembly-0/
    It's not a circlip. It's solid, like a plug. Think of a piece of wooden furniture such as a headboard of a bed with screws that hold it together. Then there is a shallow piece of wooden down that fills the scre hole. The plug is about 1/8" thick and 1/2" diameter. It covers the piston pin and prevents it from sticking out either side to contact the cylinder wall. when the plugs are in, it just touches the cylinder wall on both side. the outside is slightly convex with traces of wear from touching the cylinder walls.

    It looks like I'm going to take everything off my garage bench, move the bench and sweep the floor carefully. The damn thing just didn't disappear.

  4. #4
    dougand3's Avatar
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    Mar 2012
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    Alabama
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    Craftsman

    Re: troybilt trimmer motor bolt broke

    Sounds like an overkill way to retain the wrist pin. 120cc saws use a circular strand of metal in a groove. Maybe there is some engineering reason.
    89 Craftsman GT18 44", 4 push mowers, Lotsa chainsaws.

  5. #5

    Join Date
    Sep 2019
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    Troy-Bilt

    Re: troybilt trimmer motor bolt broke

    Quote Originally Posted by dougand3 View Post
    Sounds like an overkill way to retain the wrist pin. 120cc saws use a circular strand of metal in a groove. Maybe there is some engineering reason.
    pinston.jpgpiston1.jpg

  6. #6
    dougand3's Avatar
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    Mar 2012
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    Alabama
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    Craftsman

    Re: troybilt trimmer motor bolt broke

    Odd looking. Maybe it has to do with transfers - fuel moves better with smooth surface. Did you find the other one?
    89 Craftsman GT18 44", 4 push mowers, Lotsa chainsaws.

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