Ford 3910 starter issue

RickB · Apr 23, 2021

Unplug it and bridge the circuit. Make absolutely certain both shifters are in neutral before jumpering the safety circuit.

Birdhunter1 · Apr 24, 2021

The quick and easy way to jumper it is to cut the two wires by your shifters coming out of your transmission cover plate and use a wire nut to connect them. Leave enough wire out of the top of the trans case to be able to reconnect too if you need to hook that switch back up.
Word to the wise, the tractor would now start if it is in gear and many a farmer has been run over from cranking the machine standing next to it.

RickB · Apr 24, 2021

Birdhunter1 said:
The quick and easy way to jumper it is to cut the two wires by your shifters coming out of your transmission cover plate and use a wire nut to connect them. Leave enough wire out of the top of the trans case to be able to reconnect too if you need to hook that switch back up.
Word to the wise, the tractor would now start if it is in gear and many a farmer has been run over from cranking the machine standing next to it.

Or if you don't like the idea of butchering the tractor harness you can simply unplug the connector that joins it to the NSS pigtail and make up a jumper wire.

dflur · Oct 16, 2021

"How do you jumper around the switch?"

Unplug the two prong line that goes through the shift cover. Loop a wire to both sides of the wire that is going away from the shift cover. Be careful though. That is a very important safety feature. It will crank while in gear and take off and can run you over. There are a lot of sad stories about that.

SteveS42240 · Mar 10, 2024

I have a 3910 and a 4000 Ford that does the same thing. The contact in the starter solenoid has some corrosion on it that will not allow the voltage to pass through to the starter. Sadly, the Lucas starter solenoid on these tractors is not rebuildable so I can't get into it to polish the contacts. I keep turning the switch until it turns over. Sometimes it does it on the second try, sometimes it's several more. I do keep the battery terminals and cable ends clean so it gets as much amperage as possible.