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    Lagasse07's Avatar
    Lagasse07 Posts: 2, Reputation: 1
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    #1

    Sep 21, 2007, 10:20 AM
    Backfiring Rebuilt 12.5hp briggs
    I recently rebuilt a briggs 12.5 hp I/C motor and I can't get it to start. It will rotate but when it tries to start it backfires. I had the whole engine unassembled I'm just wondering what could have went wrong?
    MOWERMAN2468's Avatar
    MOWERMAN2468 Posts: 3,214, Reputation: 243
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    #2

    Sep 21, 2007, 04:10 PM
    Did you line up the timing marks on the cam and crankshaft closest together, not one at top and one at bottom. Always close together. Then if you timed it correctly there. I would mainly lean toward a sheared flywheel key.
    Lagasse07's Avatar
    Lagasse07 Posts: 2, Reputation: 1
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    #3

    Sep 22, 2007, 06:24 AM
    Quote Originally Posted by MOWERMAN2468
    did you line up the timing marks on the cam and crankshaft closest together, not one at top and one at bottom. always close together. then if you timed it correctly there. i would mainly lean toward a sheared flywheel key.

    Sheared flywheel key? Do you mean a missing tooth on the flywheel or the key is actually sheared. The key is fine but I am missing a tooth. Also my spark plug was wet like it wasn't firing.
    MOWERMAN2468's Avatar
    MOWERMAN2468 Posts: 3,214, Reputation: 243
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    #4

    Sep 22, 2007, 01:59 PM
    See the reply to the pm you sent.
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