HELP!! Still can't find problem!!

However, I have a 1950 M, bored, fire-crater pistons, and live hydraulics. My dad FOUGHT with the 6-volt system tried the 8-volt batter route with limited success, and he was a mechanic that worked on 6-volt systems for a living during WWII. Finally, FINALLY, I talked him into trying 12-volts. Night and day difference! After that initial start, he wouldn’t hear of going back to 6-volts. NEVER! The 12-volt system allowed him to put brighter lights and more of them on the mounted picker and made it much easier to see at night in the winter doing loader work.

I see both sides. For the restoration purist, 6-volt is the way it came from the factory (also with low compression heads and flat top pistons) and worked fine. For functionality, and lower frustration, 12-volt will spin it over faster, have more “tolerance” for bad connections (if you compare electricity to water, volts = pressure so 12 volts will push electricity though a poor connection easier than 6 volts) and usually give quicker startups. The 6-volt starter will perform and last as long if not longer on 12 volts as long as it is used just like if it was on 6-volts. I guess you have to decide which is better for you.

I won"t go on and on about the minutae of battery physics but I have run into more than a few people at various auto, parts supply outlets and even battery retailers who tell you your battery is good and simply don"t know what they are talking about or what tests to run. I remember trying to make good on a warranty, some kid telling me my dead battery was good simply because his meter told him 12 volts. There was no way to convince him and I could tell by the look in his eyes that he thought that that I was the one who didn"t know what I was talking about simply because his meter showed 12 volts. I just gave up wasting my time and went to another outlet and didn"t ask them--this time I TOLD them my battery was dead and I needed a new one and was quite adamant about it cutting them off at the pass before we started heading down the "the meter says 12 volts" road again.

If you have any other 6 volt batteries around I would try jumping it to your tractor and testing the results. As an alternate you might purchase a new one and try jumping your tractor with it before you install it. If it makes no difference you could simply return it.

If you are convinced about your terminations, your battery cables are properly sized and your volt meter (assuming you know how to properly check them) finds no large voltage drop over any component I would strongly suggest you address the battery. I suspect you might be surprised at the results.

I was doing this with my Super A for years, just barely start, often had to crank start, no long life to batteries, etc. Most people critize 6 volt and will tell you it's no good. Truth is charging system is no good. In 1992 I installed a 6 volt alternator on my Super A together with a new 6 volt battery. That battery and alternator are still in tractor and will start every time. That battery lasted 12 years plus because it was always fully charged. I doubt if 12 volt batteries do any better, I've never had one come close to 12 years.

So many times you see this here in YT discussions, "6 volt is no good, I'm changing to 12 volt." 6 volts will start any well tuned pre 1958 gas Farmall, in any weather that it is fit to be out on an open station tractor. I once started a Farmall 300, 6 volt, -40 degrees, and it stared on 3 turn of engine, completely unassisted by any boost. My dad said," I hope it doesn't start, as one of us have to drive it back to farmstead." I got selected dad took the pickup, man that was a cold 1/2 mile.

I've never had a 6 volt but as you say, if every thing is at specs there is no reason it shouldn't operate just as well as a twelve. A truly charged battery and current path will always perform as designed.

Are you sure the people who "checked" your starter and battery actually checked them? Are they reputable?

I don't put much faith in battery "checks." Those battery checkers you can get at the auto parts stores will tell you that a BRAND NEW battery that throws the engine over like a limp rag doll is shot.

As for the starter, all they can do is hook it up and see if it turns, and visually inspect the brushes.

I had this problem years ago with my Super A, someone had installed cables from an old 12 volt car. Now you would think most any cable would turn that little SA engine, not so. I changed, and the difference is unbelievable. I find the best source for these heavy cables are heavy truck supply stores. They use these on big diesels even with 12 volt. I expect by now farm equipment dealers would have heavy cables.