Coil Testing - 18hp briggs and stratton

[ragman88]

Hello all, I'm new here and just purchased a hustler. It is not getting a spark. Can anyone tell me how to test the coil? I can't seem to find any information on the internet. Also, when I put it back on, what should the gap be from the coil to the flywheel.

Thanks in advance for any reply's.

Thanks

Phil

[racerone3]

there really isn't any test for the coil, it either sparks or doesn't. when you put it back on, rotate the flywheel till the magnet is under the coil mount tabs. lay a 3/5 index card (they are about .035) on the magnet, then set the coil in place. don't push down on the coil, just let the magnet pull it down. snug up the bolts, and rotate the flywheel by hand while tugging on the index card to pull it out.

[demo61x]

mine had a diod in the coil wire that went bad. was like 8 bucks to fix.

[msafi65]

Make sure the kill terminal isnt grounded. The diode wire can fail making one or both coils dead or fail to where you cant kill the engine with the mag ground terminal. demo61x is correct should be less than ten$.

[racerone3]

If you have the flat twin briggs that came stock in the hustlers, there won't be a diode wire. those engines use a single coil with 2 plug wires as the cylinders are timed 180 degrees apart.

[ragman88]

Thanks guys.
I dropped the coil off at a small engine repair shop tonight. They said they will test it in the morning (i guess put plugs on it and see if it sparks). He said that most people that bring coils in and tested are not faulty (other problems). I hope mine is bad so I know what the problem is, lol. It is not the stock engine. The person I bought it from, I think said it had a koehler engine? He put this engine in a while back (used engine). It is a briggs model number 422447-4059-01. Is the kill terminal the small wire that plugs into the coil (not the two large wires that go to the spark plug)? If so, that wire should not be grounded? It was connected to the case of the engine, I thought that meant it was grounded. I think it's the flat twin (i guess), the cylinders are not like in a motorcycle (v).

Thanks again for your responses. I'm ready to get this thing running!!!!!

Phil

[mustangwagz]

the diode between my coils on the kill switch wire was bad as well.. odd thing, if you touch the coil paths together, they will shut motor down..so i wander just how that whole process works!? anyhow, let us know what ya find.

[ragman88]

Ok, they tested the coil (magneto) and it was bad they said. Bought a new one, put it on, cranked it and still no spark! Any other ideas to why it will not spark? There is a little box (1.5" x 1.5" x 1/4" approx.) that is mounted on the flywheel shroud, it has a red wire (power to it when the key is at the middle "on" position. with two yellow wires coming out. I would think that if power is going in, power should come out of the wires???? but nothing. What is this device. I can't see where the wires go to, go in behind the flywheel area. Any ideas?

Thanks

Phil

[cclingma]

I can understand how bad you want that thing to fire so here's a guess. I say remove any grounds on that motor except for the big heavy gauged one. I've had issues in the past where the ignition switch was grounding the coil as if in stop position even when I was in run or start position.

[cclingma]

I can understand how bad you want that thing to fire so here's a guess. I say remove any grounds on that motor except for the big heavy gauged one. I've had issues in the past where the ignition switch was grounding the coil as if in stop position even when I was in run or start position.

Reread and that's not really what I meant. I say remove all wires to motor except the one going to starter and big frame ground....then see if spark.

[mustangwagz]

Pull your fan shroud, the tin work that covers the flywheel. Look at your coils, there will be a wire than runs between BOTH coils, then over to the plastic studd on the tin work. (or there will be a wire that runs between both coils, and then goes somewhere..) Unhook that wire from both coils and see if that helps. Make sure your gap is set correctly, you can use the 3x5 notecard like stated in thee post above. Thats all you need for spark my friend..if you staill aint got spark after youve unhooked that wire, you got bad coils id say, Or bad plugs..Plugs DO go bad..ive seen it numerous times.

how are you checking for spark?

[mustangwagz]

unless you've only got ONE coil...like racer said, then i'd look at plugs N such. The voltage reg should not have anything to do with it (box with red wire and 2 yellows) Voltage reg creates DC voltage N such for your charging system. Nothing to do with spark. spark is solely controlled by flywheel and coils, via magnets. (unless its a points system...)

[ragman88]

Well, The small wire coming off of the coil was the kill switch ground wire. For some reason, the previous owner had it wired to ground (any position the key was at). The small engine place said to remove the wire and see if it sparks. Well, I had the plugs in the motor, unplugged the small wire and it started!! I could not get it stopped, so I touched the small wire from the coil to the engine case, it sparked and stopped. Pul the shrouds back on, ran another wire from the small coil wire to a toggle switch (figured that would ground/unground???) Tried again to start and no spark. unplugged the wire like before and still no spark. WOW, the son and I were excited for a minute then dang. Very frustrating to someone who knows nothing about engines. He was telling me that if I do something wrong at the switch (something, can't remember what he said) it can fry the coil. I'm wondering if that happened. guess I'll take it back to the place and get it tested again.

[ragman88]

Just saw ya'lls post, thanks for the help. Will keep trying I guess. So that stud is plastic, I did not know that, the small wire from the coil was attached to a stud with another wire going to the key switch assembly, that is what i unplugged the first time and it started. Then, no more, LOL.

[mustangwagz]

well the stud is metal, but it should be encased in plastic? is this a vanguard vtwin 18? or the older opposed (side sitting vtwin) ?

Mine was intermitent also ragman, sometimes it'd run, others it wouldnt. untill i TOTALLY unhooked wire from both coils, ran new ones to a kill switch, and just looped em together. but once you let us know what motor it is, i think we may be able to help pin point a little better.