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mikedeltasierra

Stop wire system on 3.5HP Briggs

mikedeltasierra
13 years ago

My son's mower is having an issue with the stop wire system and I cannot figure out how to correctly wire it. This is on a 1981 3.5HP Briggs engine.

There is one wire that connects from the condensor on the break points to the ignition coil armature. There is another wire that is connected to the throttle that heads back towards the condensor. Where does this wire attach?

Right now the mower will run when the wire that connects to the ignition coil is NOT attached. As soon as I attach it the mower stops. I cannot figure out what the proper set-up is.

Thanks for your help in advance.

Comments (11)

  • tomplum
    13 years ago

    The condensor will have the wire from the coil and the kill wire under the clip as well- on regular point ignition. It sounds like the coil may have been replaced w/ an electronic ignition model maybe? If the coil has a spade type connector, that wire is grounded by the kill switch to stop the spark- and doesn't use points. If the wire comes out of the lamination directly, it would be a point type coil. It certainly wouldn't run with this disconnected on a point system. The kill switch would work the same. I hope I'm not wrong on this as I see 1 or 2 point set ups ina year anymore...

  • canguy
    13 years ago

    Look on the throttle plate where the cable is attached. There may be a nylon block with a tang attached that the throttle linkage contacts when the lever is pulled back, this is a kill switch. Lift the metal tang and slip the bare end of the wire through the hole.

  • mikedeltasierra
    Original Author
    13 years ago

    Well duh on my part. We put on a new ignition coil but I did not realize that it was an electronic coil. So, I guess I will take the wires off of the condesor and be done with that. I should then run the wire from the contact on the throttle to the coil?

  • canguy
    13 years ago

    Correct

  • mikedeltasierra
    Original Author
    13 years ago

    Okay, so I removed the wires from the condensor. Now I have one wire that is connected to the plate near the throttle. I assume that when the metal plate on the throttle contacts this it is supposed to stop the engine. I also have a plastic quick connector that goes on the coil. There are 2 wires coming from that. One has a spade and the other is a bare wire.

    When I attempt to wire these in any combonation the mower will not run (no matter the position of the throttle) if I remove the plastic wire connector from the coil it will then run. i can't seem to find a way that the connector is on the coil and the engine will run?

  • tomplum
    13 years ago

    They give you a harness w/ two wires from the coil to fit different types of kill switches. So you use the wire that applies to your switch and nip the other. Some people look at that harness and ground one lead- which prevents the coil from producing spark. If it is hooked up properly and your kill switch is not providing ground in the run position- you will have spark.

  • mikedeltasierra
    Original Author
    13 years ago

    So in theory it should work correctly if I connect one wire from the harness on the coil to the wire from the kill contact on the throttle? If so, then I have a problem because it will not run in that manner. Also, when I was trying different things, with the wiring harness on coil and I touch the wire from the throttle (with the throttle open and not contacting the kill switch) it will stop the engine. Should I be looking for an issue on the throttle plate?

  • rustyj14
    13 years ago

    Well, if ya do finally get it to run, and can't shut it off, tie a piece of strong cord or rope to the spark plug wire, and when ya want to stop the engine, just yank on the rope! After the engine stops, then replace the wire on to the spark plug!

  • tomplum
    13 years ago

    Yes, your throttle stop switch must have an issue if it is grounding the coil. An ohmeter would be a good tool. Now Rusty, yanking of spark plug wires on these new fangled coils is not a happy thing....

  • mikedeltasierra
    Original Author
    13 years ago

    Okay. I'm nut a pro with a multimeter. What would I be checking?

  • tomplum
    13 years ago

    A ground is provided to the coil to kill the spark- so remove the wire from the coil. If the ground is present at that wire all the time- you need to figure out why.