Sears Lawn Tractor Magneto Question

Discussion in 'Homeowner Assistance Forum' started by graycenphil, Jun 26, 2008.

  1. graycenphil

    graycenphil LawnSite Member
    Posts: 3

    Nice site. I found it from the Plowsite.

    My Sears riding mower won't start sometimes. When it won't start, I put a plug in the end of the spark plug wire, ground the plg to the cylinder head, and it has no spark. But if I crank it and touch the plug wire to the cylinder head, I'll get a spark. It just wont jump any gap. When it is working, it jumps the gap normally. The magneto has one thin gray wire and the spark plug wire; no other connections.

    My questions: Is it obvious what is wrong? And is that wire that goes from the magneto into the wiring harness just a kill wire? In other words, if I disconnect that wire from the magneto, should it run forever? When it won't start, disconnecting that wire does not help. Am I making sense?

  2. tm14930

    tm14930 LawnSite Member
    from nj
    Posts: 32

  3. jkason

    jkason LawnSite Senior Member
    Posts: 548

    Try grounding with a new plug. Rare that they go bad, but it happens.

    The thin wire on the backside of the magneto is your kill wire. Remove that, and you won't be able to shut it off short of grounding the plug wire.

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