Ford 3910 starter issue

[sawtooth]

As the title says I believe I may have a starter going out on one of my 10 series Fords. For the past year sometimes the starter turns over perfect then others there’s only a cluck then nothing. Key off then back on and it might turn over or might “clunk” again. At first I thought I had a bad connection somewhere but after taking everything off and cleaning it I’ve had the same issue. Does this sound like a starter going out? Normally for me they just slip and squeal when going out. Thoughts?

 

[Birdhunter1]

You might jumper around the neutral safety switch for a while and see if that resolves the issue, I did on mine and it turned out to be the issue. The switch was easy to replace.

 

[RickB]

You might jumper around the neutral safety switch for a while and see if that resolves the issue, I did on mine and it turned out to be the issue. The switch was easy to replace.

Good advise.

 

[sawtooth]

Never even thought of that as I’ve had to replace those before. They seem to go out fairly frequently. Thanks and I’ll give that a shot first.

 

[RickB]

Some of those deals have a small floating pin that moves the switch. They can wear a little and throw the switch out of adjustment. A new switch works for a while then breaks in a bit and quits. Rinse, repeat.

 

[Roadworthy]

It's also possible the contacts inside the solenoid are pitted and not making good contact.

 

[Texasmark]

Jumpering a voltmeter across the "coil activating" terminals during starting will tell you if the solenoid coil is getting power...which excludes starter switch, safety switch, and wiring if present. Jumpering across the solenoid with a pair of common pliers, (my usual method) will test the solenoid contacts.

Moving the Range Lever back and forth, changing nothing else will identify the safety switch as the culprit. My 1988 3910, bought a couple of years ago with 900 hours had such a problem as I could wiggle the range switch and when I found the sweet spot the tractor would light off immediately. Recalling, and somewhat vague, the problem was the same as "Birdhunter's". I bought a new switch and installed it and it helped but didn't give me 100% reliability.

In investigating the actual depression lever to switch contact, I found that the lever wasn't pushing the ball bearing down far enough. I installed a flat washer somewhere in there and that increased the depth of the lever's penetration such that it was adequate to cause the switch to close reliably.

Don't remember all the little details, but my problem was that the Range Lever wasn't pushing down on the switch hard enough. In summary, you may be able to fix your problem as I did and save the cost of a new switch, or may purchase a new switch and it fix it, or you may have to do as I did and if you buy a new switch and it doesn't work, shim it with a flat washer..or two...forgot where I put the shim. Good luck.

 

[srsnitch]

You might jumper around the neutral safety switch for a while and see if that resolves the issue, I did on mine and it turned out to be the issue. The switch was easy to replace.

Where is the safety switch located on your machine?

 

[RickB]

Where is the safety switch located on your machine?

Under the transmission shifter cover.

 

[srsnitch]

Good advise.

How do you jumper around the switch?

 

[RickB]

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

 

[Birdhunter1]

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]

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]

"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]

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.