D15 positive ground pertronix

My D15 has recently popped two 12 volt positive ground pertronix kits. Tomorrow I will be switching it back to the points. I have the 3 ohms flamethrower coil from pertronix along with the kit. I have the a system setup on my D17 and have run it for 3 years now without any trouble.   Both times I installed the pertronix kit and ran the d15 for a few days without any trouble the weird part is both times it blew I left the tractor idling about 1/3 to half throttle for maybe 15 minutes after a cold start and it was running perfectly right till the point it backfired shuddered a little and then died. After that it wouldn't restart and when I got out a timing light to check the spark there is no spark. Same thing both times. The first time there was a fuse holder wired into the key switch that went nowhere so I thought maybe that wire had shorted out I removed that and now the ignition starter voltage regulator and genorator and amp meter are the only things wired up on the tractor.   The genorator was recently rebuild and the voltage regulator replaced. The starter is new.   I bought the first pertronix kit because it quickly burned out a set of points in maybe a month or two of work.
I was wondering if a bad voltage regulator could be causing my trouble.   I don't know what to check next on this one.

Edited by Dan73 - 17 Feb 2016 at 4:48pm

What voltage is your generator putting out? Use a good voltmeter, not a cheapie one.

I'm with Hubert about the genny needing to be polarized. Odds are the shop rebuilding it might have done it negative ground being the most common 12V system for testing it out. What happens is the genny will try to 'reverse' charge the battery, which is really bad in the long run...BTDT, sigh
I lost a great semi battery on the Gleaner cause I thought it was  a negative ground system and hooked the battery up with -ve going to ground.
I'm sure Steve from B&B will have 'words of wisdom'...

Jay

Oh the battery will pass a load test. I think it is a couple of yeas old but I did load test it and it was fine.

If I was a bettin' man, I'd say you have something spiking the module. Whether it be and overcharge problem, a short, bad ground, or a Battery starting to fail, something is wackin' the module. Obviously, its not the E.I. because its cookin' points also. What I would do in the meantime is send both blown modules to Pertronix for diagnosis. Let their tech crew tell you why the modules blew. While they're out getting checked, start doing some checks on the Tractor. Output from the Gennie, draw test the Battery, cleaning ALL grounds, including making sure the VR is grounded correctly. (very important) Inspect the wiring system for rub throughs on the torque tube or under sheetmetal. There is a reason why those modules popped and why that Tractor eats points for lunch. Remember, temporary loss of ground can do the same thing...
Steve@B&B

Dan, take a look at the wiring diagram I posted on the thread about my D15 generator question. That is the way I wired mine for negative ground. Mine has the start position in the switch and not the original separate push button. There is a diagram available for that one also. But Steve be da' man on all of your electrical questions.

Dan,
 You got the best AC guys looking over your shoulder. Electrical trouble shooting is not my strong point. I wish you the best.
Regards,
 Chris

Eating points as well as Ignitors, I'm going to bet charging voltage is getting too high or a bad connection in the primary circuit. You might check the coil just for kicks to verify it is in fact 3 ohms.

Charging voltage can go high if the battery circuit connections are poor. They do need to be cleaned every couple years, but usually affect starting before they affect charging. The battery chemistry is very good at holding voltage when charging until the battery is really overcharged (evidenced by loss of electrolyte). A generator that charges at just above engine idle with a faulty regulator or wiring will generate at least twice that voltage when the engine speed is twice the idle speed. Thinking about 800 RPM for idle charging and 1600 RPM is easily within the engine speed range.

The ammeter is a good test for proper generator voltage regulation. Right after starting the charging current should be maximum, then as the battery charges in a half hour or so (depends on that maximum rate and the battery size in ampere hours) the current tapers off and in a hour or so the battery current should have tapered to zero. If the voltage regulator isn't working it won't taper. If the voltage regulator is simply too high a voltage the current won't taper. If the current doesn't taper the battery gets low on electrolyte and won't crank good and won't hold the voltage down.

Burned points come from too high a current, usually from a 6 volt coil on 12 volts without a resistor to limit the current. Then usually both contacts are burned. If the condenser is bad or the wrong value, metal will migrate from one point to the other, one develops a hole and the other a point which make setting the point gap with a feeler gauge impossible. That metal migration doesn't require high current. A condenser open or way away from the proper value tends to lead to a skinny orange or yellow spark. The right condenser gives a fat blue spark at the plug.

Gerald J.

Thanks for all the replies.   I do have a nice multi meter. I will dig it out and so some testing tomorrow.   The more I think about it the more I wonder how the wiring to the genorator is.
I have been a little under the weather with an infection in my hand the last few days it I'd getting better but between it and the antibiotics I have been pretty wiped out lately. But I can actually grip things today without the pain beings to the point where I just want to drop whatever it is. My hope is to be working on the tractor tomorrow and to get the ice and snow out of the driveway.
Thanks again for the advice I know what to look for now just need to trace it all out and check the voltages.