No Spark

oneleg

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I have a snapper rear mount mower with a 12.5 briggs and stratton Intek engine. it wont fire unless I disconnect the coil wire. Cranks and runs fine with coil wire disconnected. How can I fix this?
 

cpurvis

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One would have to assume that you're talking about a kill switch wire. How do you shut the engine off with the wire disconnected?

Use a voltmeter to check to see if the wire you're talking about is grounded. If so, it must have a short to the frame somewhere or the switch is bad.
 

oneleg

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One would have to assume that you're talking about a kill switch wire. How do you shut the engine off with the wire disconnected?

Use a voltmeter to check to see if the wire you're talking about is grounded. If so, it must have a short to the frame somewhere or the switch is bad.

Thank you for your help! Was thinking bad coil wire. Switch cranks mower fine with coil wire disconnected. Just trying to find out if anything other than the switch or bad coil wire would cause this problem. Can shut off the engine by touching the wire to the bracket that I disconnected it from!
 

cpurvis

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Thank you for your help! Was thinking bad coil wire. Switch cranks mower fine with coil wire disconnected. Just trying to find out if anything other than the switch or bad coil wire would cause this problem. Can shut off the engine by touching the wire to the bracket that I disconnected it from!

OK, no need for a voltmeter, you've already answered the question as to whether the wire is grounded or not. It is; and it isn't supposed to be.

Find out where the wire goes and disconnect it from whatever switch it is connected to. Reinstall the other end of the wire on the coil and see if the engine fires up. If not, the wire is shorted out. If it starts, the switch it's connected to is bad.

Replace whichever one of those two is defective.
 

oneleg

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OK, no need for a voltmeter, you've already answered the question as to whether the wire is grounded or not. It is; and it isn't supposed to be.

Find out where the wire goes and disconnect it from whatever switch it is connected to. Reinstall the other end of the wire on the coil and see if the engine fires up. If not, the wire is shorted out. If it starts, the switch it's connected to is bad.

Replace whichever one of those two is defective.

The wire runs from the coil to a bracket on the side of the engine held there by a nut. There are two more wires connected in the same place. Both are black. I assumed they were ground wires for the key switch and the safety switch under the seat. Should I trace these wires to where they go then disconnect each one at a time from the bracket to determine whats bad?
 

ILENGINE

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Or you can disconnect the wires and run a continuity test on each wire to ground and then trace which wire is shorted out.
 

oneleg

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Thanks for the help! Didnt think about a continuity test! Gonna give it a try!
 
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