D2 5U electric pony motor starter problems

How about a picture of your starting arrangement.
What you show is a generator, not a starter although a generator can be wired as a motor, usually only done for testing. Continuous or heavy use of the 6V generator on 12V can be destructive but starters seem to survive just fine if you don't crank them to death.

I don't have a picture but it is mounted to the firewall/dashboard with the shafting protruding to the inboard side running a V belt to the pulley on the front of the pony. The cable from the battery is mounted to the A(armature?) pole. There are two smaller wires, one from the A pole and one from the F(field?) pole that run back behind the the firewall.

a photo of what is acctually bolted in place on the machine would be helpful this may have been old farmer ingenuity repaired or converted at some stage. i have a stanionary engine at home that had a old cream can for a hopper the original had broken or rusted out so they used that instead we put the correct hopper on it but still have the cream can one day i'll mount it with a sign stating what it was used for.

OM is correct that is a generator. starters are longer, skinnier and have a drive housing on the business end to allow the driving pulley to free wheel one the engine starts. yes stater generators do exist on other equipment but they have special regulators to make that work.

as for running it on 12volt not a good idea unless it has been converted to 12volt. dont worry 6v batteries still exist you probably have to go to a specialist battery retailer to get them though.

don't mean to be a downer, but i wouldn't spend any $$$ or spend any time chasing anything 6 volt, generators, starters, batteries etc....just too obsolete nowadays... way too many 12 volt pieces available

OM is right that starters last pretty good on 12V if you don't crank them too long--have 12v on my D2 and D4 for years--

If you must use a generator for a motor just about any Delco Remy unit would do. The one you have looks very similar to the one on my Case 530CK. A 12v unit is going to spin slower than a 6v unit with 12v power.

I'd have to disagree somewhat kittylover123. True, 12v is ubiquitous and more affordable, but if a fellow wants original, 6v works very well. My 5U is fully 6V (generator, battery, pony starter) and it starts and charges just like any other regular vehicle. The only material difference in the setup is the size of the battery cables, which are 00 and that I supplied. It didn't have a battery when I bought the tractor so I had to buy one, but they're available. Matter of fact, I'm impressed with this battery which never gets any love other than the half dozen times I run it per year, but the way it holds charge, I'd swear it was brand new.

i knew i was gonna catch some flack over that one....good one Neil !

-but i said "chase", chasing....because there is very little reason to...Okay original, nice... stuff i have lying around, stuff i can make work or make do, okay i do that too...and i'm sure the 6volt starters would last if not abused...perfect...absolutely use what you got....but realize the limitations you are dealing with...

-but there may be a reason Cat went 24 volt....maybe before anybody else?