9N Electrical Help

The tractor was starting really hard, and wouldn't restart warm, so I decided to do a tune up. It is a front mount dist. with a 12 volt conversion. The coil wire went to the ammeter with a resistor, then to another resistor, then to the key. From what I have read, I'd assume this is the setup for a 6V coil on a 12v conversion???

For the tune up, I put in new plugs, wires, new cap/rotor, points, and a coil. I followed all the specs for gaps, etc. Happily the tractor started right up and sounded stronger than ever. While putting it away, it stumbled a few times, but I got it put away. I got it out tonight to mow the pasture, and it started right up, but stumbled a few times again, like it was loosing ignition. It finally stayed running and I got it hooked up and started mowing. after about 20 minutes it bogged down and started stumbling again. It stalled and wouldn't restart. I let it cool down and it wouldn't restart. I started looking at the wiring, and pulling stuff off. I took off the resistor (not part of the ammeter, and it basically crumbled. So I went to TSC to see if they had any (no luck), but I picked up a new harness, ammeter (no resistor), new key switch. Figured if I was going to fix it, might as well do it all. I want it to be reliable.

Where I think I messed up was, while at TSC I noticed they had coils for 6V and 12V. (both look exactly the same on the outside). So I thought maybe I put the wrong replacement coil on. I didn't pay attention when I bought it, just went on looks. When I got home, of course the coil package that I bought didn't have 6V or 12V, like the other coils did in the store, so I don't know what I have.

So the help I need is to understand what damage I did? Are the points going to be shot when I remove the dist.? I'll stop at TSC tomorrow to cross reference what new coil I bought, but did I fry it, if it was the wrong one? From what I've read, it sounds like the easiest way would be to buy the 12V coil, and use no resistors. Is this right? Maybe the new coil was a 12V and thats why it didn't run right with the two resistors?

Please shed some knowledge on me and/or email me any helpful documents/diagrams you might have. I need to get the old girl running,, the pasture is getting tall.

Yer problem as described, run fer about 20-mins and starts to stumble and quits is "classic" weaksister ignition switch. $10 (cheap)

All yer other stuff you replaced, probably needed it. But you're other concern about yer squarecan ignition coil, is NOTTA problem. Why? 'cuz cuttin' 12-volts down with 2-resistors to run a 12-volt coil ain't even gonna start. You claim after yer tune-up, instant starting. Thats means yer new unlabeled squarecan coil is a 6-volt coil running on 12-volts cut-down by 2-resistors. Just like it should.

You should ALWAYS check yer ignition points 'cuz new points seem to slip fer summ reason.

As to whether to change to the 12-volt squarecan ignition coil, I would, but it still needs the "infamous ballast resistor". Which is the resistor you describe as self-destructing. Yer current 6-volt squarecan coil plus 2-resistors worked well for you. Your call$$$

Unfortunately, squarecan coil mfgrs haven't figgered out how to label their plastic shell with part numbers or operating voltages, but they've figgered out how to label the country of mfgr. Go figger..... .....Dell, yer self-appointed sparkie-meister

So if I am going to stick with the 6V coil on a 12V conversion, what do I need for resistors. I have read about getting them at radio shack, or the local Napa, but what do I need to replace the ballast resistor and resistor on the ammeter.

Thanks.