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MF 231 Voltage Regulator

MF 231 Voltage Regulator

I have a MF 231 (1992 model made in Poland with square fenders) that is often difficult to start. It will start fine when I jump from the solenoid to the starter. I've checked the ignition switch, neutral safety switch, solenoid, and starter and all seem to be fine. I now think it may be the voltage regulator (part no. 1079380M91) attached to the back of the alternator (see photo). Has anyone had any similar issues and could it be the voltage regulator causing the problem? Also, I've called some M-F dealers and find the voltage regulator part may be discontinued. If that is the case, does anyone know of an alternate voltage regulator that will work? Thanks for your time.

ponymare When you say it starts fine when you jump from the solenoid to the starter, is that using a screwdriver between the posts, or jumper cables from another battery source? If the tractor battery seems weak, it might be the alt or reg, if the battery is strong, then something isn't making good contact in the wiring.
hymie2lt I can get a new voltage regulator...if you find that you may need one.

Re: MF 231 Voltage Regulator

I start it by unplugging the yellow wire on the solenoid (see photo) and using a jumper wire from the solenoid to the starter. I then reconnect the yellow wire to the solenoid. At first, I thought it was the ignition switch. I bought a new one and tried that. That did not fix the problem. I bypassed the neutral safety switch and that did not fix the problem. I pulled the starter and solenoid and took it to a shop to be tested and they were both operating fine. I bought a new battery a couple of months ago and that did not fix the problem. I check the voltage at the battery with the tractor running and the alternator seems to be charging fine. I even took the wires off everything and brushed them up with sand paper and that did not fix the problem. With the tractor off, I get 12+ volts at the battery, but sometimes when I check the voltage coming into the starter it is below 12 volts and the tractor will not start. Sometimes I will get 12+ volts at the starter and the tractor will start normally without the jumper wire. So that is why I am thinking voltage regulator. But I am not certain that is the problem.

ponymare When you check voltage at the starter and get less than 12 volts, has the tractor been sitting unused for a few days? If so, then there is a current drain, it could be the reg or alt.
Ridger Yes. I keep the tractor at my farm and usually use it on the weekend. So it sits unused throughout the week and maybe longer sometimes. I never thought about a voltage drain. Should I pull the alternator and take it to be checked out? Any suggestions? Thanks again for all your help.
ponymare Wouldn't hurt to have it checked out, also look for other things that could be drawing current.

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