Question about Tecumseh Garden

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Am looking for a tecumseh ULT50 manual

Lawn mower fires once and then that's it. Sometimes backfires as if too far advance. Have checked everything, valves, clearance, carby, spark, flywheel key and all OK. Any ideas

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  • Bob Kirkwood Feb 20, 2012

    Yes I have reseated the valves

  • Bob Kirkwood Feb 21, 2012

    Thanks, the compression is fine with no wear on the bore and no piston slop. Am going to pull the carburetter apart 'again' and triple check everything and maybe replace some gaskets. Just one more thing to mention is that when trying to start the mower, after it fires the once it then appears to want to run backwards and pulls the starter cord from my hand and winds it up tight. This one is really doing my head in!The timing appears to be non adjustable, but, could the ignition module somehow be faulty? Firing intermittently perhaps. Reluctant to spend $50 on something that may potentially sit on a bench as a spare. Thanks again to everyone.



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Hello, since you checked all of that there ,what is the compression,should not be below 60 lbs any thing lower and will not run,check for a bad head gasket and proper compression should be between 60 to 130 lbs,hope this helps,

Posted on Feb 20, 2012

  • pamabell Feb 21, 2012

    hello, i am wrong but replace the fly wheel key

  • nightstormel
    nightstormel Aug 12, 2014

    I couldn't find oversized rings. Compression low, flywheel key was deformed. so I replaced that. My end of line decision, toss it, go to a yard sale, and buy a better mower to work on. It's a garbage mower anyhow. Good luck


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Weak valve spring, stuck valve? Compression test may come out fine(60 plus lbs), but then when running, it may bind and stick, or not close in time consistently. I currently have one where we believe there is too much crank case pressure building up. When you turn it over, bubbles come out of the oil fill orifice. Guessing it's a plugged vent. Probably not your issue, but putting it out there.... Good luck.

Posted on Jun 15, 2012

  • Bob Kirkwood Sep 24, 2012

    Have finally sorted the problem after speaking to an eighty five year old ex maintenance worker. Apparently, sometimes the crank gears, located by removing the baseplate, coupling and sump cover slip gears and hence the timing goes out. Still don't know how this can possibly happen but it had. Removed gears and put back to where it should had been, reassembled and worked first time. It took a while but I got the result in the end. Thanks to all that responed. This is a repair worth remembering. Cheers, Bob

  • nightstormel
    nightstormel Aug 12, 2014

    Personally, could not get over-sized rings. Solution, go to a yard sale and get a better mower to work on. Stop throwing money away.



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Posted on Jan 02, 2017

SOURCE: carburetor linkages for riding lawn mower

Go to a tecumseh website and get a breakdown of the parts list and that should help a bit. Good luck.

Posted on Mar 26, 2009

SOURCE: Craftsman lawn mower running bad with Tecumseh

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