51 A problem

51 a rebuilt motor new carb new vr new coil new points and condenser tractor rewired correct amp mter shows charge the tractor runs from 20 mins to 1 hour and dies like you shut off ign and starts back up with no problem i dont think it is a fuel problem because when it dies it does not sputter or cough. any help would be appreciated

Chad:

To isolate the problem, hook a timing light to a spark plug and when it dies watch the light as it rolls to a stop. If the light flashes to the very end, look at fuel supply, if it stops blinking, look for a bad connection, over heating coil, or an intermittent problem in the ignition switch.

My A was doing something similar about 15 years ago. It was the ignition switch. I'd replace that and check all your connections and wires.

this is common when guys built them too tight also & when they get warm the pistons seize in the bore. in about 15-20 seconds it frees up again but when this happens it should begin to labor as it dies not just quit like shut off.

Three things: where did the coil come from? If it is a TSC special,,,they have driven me nuts: first off the windings and oil are all lighter and thus less resistant to heat than a coild from Deere (yes I know they are also $50 cheaper), but NAPA offers a good coild also for less than Deere and Steiners has a decent coil AND a HD coil both for less than Deere but better than the TSC. One day during a plow day I cooked a coil on my 70...the only place that was open eas TSC...it took 3 tries...the 1st 2 I bought were bad right off the shelf (My brother is in the auto parts biz...says they are happy if only 33% of the cheap Chinese coils are defective when new.
I have also had a condenser that intermittently acted out from new, so don't rule that out either.
Finally, I assume that since your tractor came factory as a 12v it stil is...do you have the proper coil in that you may need an inline resistor: if your coil says "12v with interenal resistor" you are OK w/o one...if your coil says "6v" or "12v no internal resistor" then you need to put one in line in front of the coil in the wire running from the ignition switch to the negative post on the coil. Good luck!