Allis G won't charge when running

I am new to using a G and working on old tractors.  This spring I cleaned the carb and sparks, and cleaned the points on the distributor and got the thing running, worked it for a bit, and noticed that the battery isn't charging.  The ammeter doesn't move to C when the engine is running, and it seems that after about 20 min of working it, it kills and won't stay running.  I can sort of keep it running if I hold the choke out all the way, but obviously not very well.  This was the case at the end of the season last year, but it would usually work again after it cooled down.  I'll be working it again today to see if the same thing will happen.  And although it runs for a while, at the end of the row that I am cultivating, a lot of the time it gets stuck revving and revving, but feathering the choke seems to remedy this.  I know that it has been converted to negative ground and it is a 6v system.  I pulled the sparks yesterday after it killed and they were pretty black except for the center electrode, and the black rubbed right off with my finger.  There also is a little puddle of condensation under the dust cap on the distributor when I check it.  I seem to have pretty good gas flow at the end of the gas line before it goes into the carb, and since I just cleaned the carb again, I don't think it's plugged up.  Last fall when I first got it started after it was sitting in a shed for a while (we rent the farm and tractor) I patched the gas tank with J and B weld and cleaned the tank, but maybe there is more rust?  I will see how long it runs today after it sat overnight.  Any thoughts would be great!  Gotta plant potatoes and cultivate more beds!

Yeah, the battery is new last year...

Good advice here. It seems you have multiple problems and some may be caused by several things. Sounds like a gas flow problem if choking helps keep it running. That could be anywhere from a floating piece of junk in the tank that eventually gets sucked over the outlet hole to a float or needle sticking.
 After you figure out the running problem, try polarizing the generator properly. It might just need a jump to get it charging.

Oh, and also pulling the choke out didn't seem to keep it running this time...

After reading all the posts, the answer is in there. In your first post I think you said that it had been changed to negative ground. If that is so just follow the instructions others gave about wiring and it should help. When you start it in the morning, pull the coil wire while running (use shock protection) and look at the fire. Now all the old timers setting around the heating stove always said that you wanted a blue and yellow fire, with mostly blue. They were of a consensus that all blue or yellow didn't work to well. I do know if it's all yellow forget it.

Sorry Gerald, I stepped on your post somewhat. Didn't mean to sound pretentious. 

A couple tests for the ammeter. You need a resistor or lamp load that will draw say half of full scale, like 10 amps for a 20-0-20 scale. Connect the load between the positive terminal of the ammeter and ground or the negative battery post. To check the charging side load the battery for a while and then connect a battery charger with the same connections to charge through the ammeter and compare the charger's meter to the tractor ammeter. They should agree. If they don't and the ammeter doesn't show charge its either not wired right or has rusted fast and needs to be replaced. A slightly handier connection point for both of these tests is the B terminal on the voltage regulator or cutout. For six volts a suitable resistor would be 0.6 ohms. I have used iron wire to test a computer power supply needing such a load.

Gerald J.

first7letters wrote: hmm, what if there isn't a light on the tractor?

Yellow spark most often comes from a bad condenser.

A 120 volt shop light wont draw much current on 12 volts and is hard to predict what current it would draw so its hard to use it to check the ammeter calibration. A 6 volt headlight bulb could be a better test.

Gerald J.

I have G that eats condensers at an alarming rate. Why?

So I finally caved in and called my cousin who is a tractor mechanic.  The wire going from the starter to the ammeter was bad so I had weak spark.  That also fixed the charging issue.  There were some tiny channels inside the carb that he had to take back to the shop and heat up to get cleaned and the casting on the main jet needed to be leveled to seat properly.  He replaced the points on the condenser for good measure and adjusted the timing and idle screw and governor screw.  Now it runs like a dream and purrs like the kittens that were born in the pole barn later that day from our best and favorite mouser.  Best couple of hundred spent all month.  Thanks all for your help.