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Can you test a coil?

Posted: Fri Oct 31, 2008 3:49 pm
by Dieselrider
Just finished rebuilding my mower deck today. It sounds nice and quiet. I backed the cub 184 out of the shop, with all intentions of trying out the deck and the tractor just died right there. Would crank but not fire. I suspect the coil. I hooked up a volt meter between the wire to the distributor and ground on the tractor, I get nothing. Is there a better way to check it?
Thanks,
DR :tractor:

Re: Can you test a coil?

Posted: Fri Oct 31, 2008 4:32 pm
by Bigdog
You will only read voltage there when the points are open. You should have voltage on the other primary terminal of the coil when the switch is on. One way to test the coil would be to connect a grounded sparkplug to the coil output and then use a screwdriver to open and close the points. Each time the points open you should get a spark.

Re: Can you test a coil?

Posted: Fri Oct 31, 2008 5:04 pm
by Eugene
I think you need the wiring diagram for the 184. There are several switches and a safety switch or two affecting the ignition system.

Just me. I would remove the distributor cap and block the points open. Then with the ignition switch on and a multimeter, start checking for voltage at the distributor - working back along the ignition system until I found voltage.

My guess as to the problem. Open in the ignition circuit. Wire came loose, safety switch open.

Re: Can you test a coil?

Posted: Sat Nov 01, 2008 8:12 am
by Dieselrider
If a safety switch was open, it wouldn't let it crank, right? This is cranking very well just not firing.
There are two examples I can think of, that stop the tractor from turning over. 1) If it stalls when mowing you must turn the pto off or it will not crank and, 2) if you do not push the clutch in, it will not crank. I am not familiar with any situations that will prevent it from firing but allow it to crank. If you know of something different, please tell me. Thanks.

Re: Can you test a coil?

Posted: Sat Nov 01, 2008 9:06 am
by RaymondDurban
Dieselrider wrote:If a safety switch was open, it wouldn't let it crank, right?

You are correct, the switches kill power to the starter, not the coil. Even the oil pressure switch just gives you a light, with no affect on power to coil. I would do what Bigdog suggested, along with a multimeter checking 12V on the hot side of the coil and ground on the negative side with the key on. Dirty contacts inside the ignition switch will also give you the same problems you have.

Re: Can you test a coil?

Posted: Sat Nov 01, 2008 9:43 am
by Eugene
http://ihregistry.com/wiring/K17.pdf

184 wiring diagram, above. Multimeter. Start checking the ignition circuit at the points. The solenoid and ignition circuit seperate at the PTO switch. A faulty contact in the PTO switch or an open in the circuit would let the engine crank and not start.

Re: Can you test a coil?

Posted: Sat Nov 01, 2008 1:37 pm
by Dieselrider
I found it. I had spliced some wires (I don't remember why- maybe a bad plug) behind the dash once before. I had voltage at the switch and none at the coil. With vibration and time the wire nut just wasn't allowing a connection there. I just got done giving the deck a trial run. Maybe I should consider a rewiring job on the cub this winter.

Thanks guys for the help.

Re: Can you test a coil?

Posted: Sat Nov 08, 2008 8:46 pm
by Garland Terry
Lick your small finger and put it inside the coil contact firmly grasp the the frame and have your wife crank the engine. She will want to help more when she sees the reaction...... :twisted: :twisted: :twisted: Now don't you dare do that!! have one of the kids do it GT