Can't turn off the sparks

Out bushhogging today, our 65 3000 gasser ran just fine...it liked working so much that it wouldn't shut off back in the barn. I pulled the ground cable at the battery post, figuring that would stop it - no dice. Finally shut it down with gas tap off & pulled the choke. I touched the ground cable back on the battery post and could hear some clicking (not the starter relay, as far as I could tell) and there was a crackly spark at the ground clamp as I touched it to the battery, so something was still hot. No, I didn't try to do that again - left it disconnected.

Went through the shop manual. Could it be the voltage regulator? It still has the generator. As near as I can tell, the voltage regulator appears to be the only possible path for a back feed to the ignition system. Do these Lucas/Prince of Darkness regulators have a failure mode like that? Of course, another possibility might be a shorted wired somewhere - all wiring is original. But before I go tearing into that original loom, thought I'd ask about these VRs.

Thanks!

(p.s. - I did cruise thru the archives first...found plenty of no-sparks/weak-sparks but nothing like this, with sparks that won't quit)

I can not say if the V.R would do that or not but I do know it is more likely to be a bad ignition switch. One way to figure that out would be to pull a wire off the switch or maybe even the coil

I also thought 'bad switch' until I pulled the battery ground cable and it didn't shut down. I'll look at the schematic again to see if that might be possible. Thanks.

Any charging system if it is working will do just that since you do not need a battery for it to run once started, that is also a good way to burn up the charging system and or get your self hurt. When you pull a battery cable off your charging system sees a dead battery so the V/R in turns tries to put out max volts and max amps and that can lead to you getting dead if you got between the battery cable and the battery. it only takes a Milliamp to kill you and a generator will put out around 35 million times that much

if the generator is charging.. why would pulling the bat cble do anything? genny will provide juice to the coil.

i'd be checking the ignition switch wireing.. gasser 3000 should have a resistor wire in run, and a bypass for start..

Thanks! Wasn't planning to do that pull-the-ground-cable thing again and this'll make sure I won't do it now. I had an insulated-handle wrench and grabbed only the insulated part of the cable, so I got lucky this time.

I'd figured that if I pulled the positive cable, it might keep running because of genny output, so it was a surprise when it did so after pulling the ground cable.

So, even if the generator & VR was ok before, it might not be now.

Won't be able to work on it for a few days, will post back with what I find.

Thanks again, Soundguy & Old

(quoted from post at 21:26:21 11/05/12) Thanks! Wasn't planning to do that pull-the-ground-cable thing again and this'll make sure I won't do it now. I had an insulated-handle wrench and grabbed only the insulated part of the cable, so I got lucky this time.

I'd figured that if I pulled the positive cable, it might keep running because of genny output, so it was a surprise when it did so after pulling the ground cable.

So, even if the generator & VR was ok before, it might not be now.

Won't be able to work on it for a few days, will post back with what I find.

Thanks again, Soundguy & Old

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ith a generator system & electro-mechanical voltage regulator, unless you keep it running while disconnecting the battery for a period in excess of several seconds, maybe 10s of seconds, you won't hurt the equipment (or yourself). Tractor generator won't output a hundred volts like an alternator can, so the caution really applies where you have alternators & solid state regulators.
A transient spike can occur upon disconnect/connect, but where no SS components are used, no harm. So, you didn't likely harm your tractor & you were not in any danger. Yes, as Old said, a milliampere can kill, but you need the wires implanted in your brain or heart. In your external limbs, you need 2 or 3 HUNDRED times that much current & even with a sweaty body, that equates to well over your DC generator's maximum output voltage in order to obtain lethal current levels. It is always better to be overly cautious that not cautious enough, but overstating the danger is a good way to cause people to become complacent & careless. Cry 'wolf' un-necessarily and soon people don't pay any attention.

Generator system as a tad bit more forgiving then an alternator system is so you probably did not hurt and thing but no matter what not a good thing to do or try. As for which cable it does not matter because a battery has an in and out and it does not care which you unhook your still eclectically doing the same thing. Takes 2 wires to make things work and if you remove either one things stop working unless it is a charging system and a battery then the charging system keep working just not charging the battery any more. Also if you have lights turned on when you unhook a battery you can blow them out at the same time

Yes, in hindsight (20-20), I should've remembered that the coil is separately grounded and would've kept firing even with the battery isolated, as long as the generator was working.

Thanks for the words that I might not have hurt the generator or VR. However, also in the 20-20 hindsight vein, I'll have to see if I've toasted the Pertronix electronic ignition that I put in it (and have liked ever since I installed it).

(quoted from post at 00:50:30 11/07/12) Yes, in hindsight (20-20), I should've remembered that the coil is separately grounded and would've kept firing even with the battery isolated, as long as the generator was working.

Thanks for the words that I might not have hurt the generator or VR. However, also in the 20-20 hindsight vein, I'll have to see if I've toasted the Pertronix electronic ignition that I put in it (and have liked ever since I installed it).

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ou say you still have spark....then the EI is working!

Ya an electronic ignition is not as forgiving and may be hurt but then it may last a day or years one never knows for sure with electronic stuff. Still remember back years ago when I still did electronic repair a stereo we got in for repair I shorted out a IC chip and it cracked and you could see the crack but in doing so it worked perfect. We let it play all day every day for a week turning it off and on once in a while and it worked as it should