Oil & Fuel John Deere F935 Fuel Shut-Off Solenoid

[CamperMan]

I have a John Deere F935 72" front mower with a Yanmar 3 cylinder diesel engine.
There are three wires that go to the fuel shut-off solenoid (1 white, 1 black, and a smaller pink wire).
When I turn the key ON the white and pink wire get 12-volts. After a few seconds a relay in the control module "clicks" and the white wire looses 12-volts. Is this normal? Does anyone have a F935 or F925 that can tell me if this is normal?

 

[Willl]

Fuel solenoids on todays engines have 2 coils built in to them, all operating the same plunger.

The first is a 'pull in coil' drawing higher amps.

The second is a 'holding coil' that draws lower amps.

 

[kennyd]

Welcome to TBN

Are you having a problem? Maybe if you describe it we can help you further...

 

[CamperMan]

Thanks for the replies. My solenoid must be bad because the solenoid does not stay open.

I bought this used F935 about six months ago from a guy at a swap meet. He acquired it from an estate auction and did not have any history on it.
I did not want to list all the problems thinking it might confuse readers and possible influence the answer/s.

I have had different problems with it and am wondering if they are related. Originally it would start but took some time to reach full throttle. I thought this was normal and meant the motor was not warmed up yet.

Problems I experience:

• I mow fine for a while and then the PTO shuts off. I then move the PTO switch off and on and the PTO engages normal for a while then shuts off again.
• Mowing normal and the engines tries to die? To keep the engine from dying I return the foot pedals to neutral and the engine idles? If I give it forward or reverse it dies.

I am also wondering if these problems are related to the interlock (safety system?eat switch, brake switch, etc.).
Thanks again for the help.

As for my aviator? I found out the hard way NOT to use my 25,000-pound CAT951C after weeks of rain. I left it in the ground for a few months and had my country neighbor help dig it out with his New Holland skid steer.

 

[CamperMan]

Thanks for the replies. My solenoid must be bad because the solenoid does not stay open.

I bought this used F935 about six months ago from a guy at a swap meet. He acquired it from an estate auction and did not have any history on it.
I did not want to list all the problems thinking it might confuse readers and possible influence the answer/s.

I have had different problems with it and am wondering if they are related. Originally it would start but took some time to reach full throttle. I thought this was normal and meant the motor was not warmed up yet.

Problems I experience:
I mow fine for a while and then the PTO shuts off. I then move the PTO switch off and on and the PTO engages normal for a while then shuts off again.
Mowing normal and the engines tries to die? To keep the engine from dying I return the foot pedals to neutral and the engine idles? If I give it forward or reverse it dies.
I am also wondering if these problems are related to the interlock (safety system?eat switch, brake switch, etc.).

As for my avatar? I found out the hard way NOT to use my 25,000-pound CAT951C after weeks of rain. I left it in the ground for a few months and had my country neighbor help dig it out with his New Holland skid steer.

 

[Fill Dirt]

I have an F935 and am having the same problem! According to the service manuel the one wire is supposed to pull in the solenoid and then the other wire is supposed to hold in the solenoid! Both of my wires loose power at the same time! There is a bracket behind the solenoid that is used for a cable which I have used to replace the solenoid I just manually turn on the shutoff just like on my John Deere 750!

 

[Spudland_Dave]

My solenoid must be bad because the solenoid does not stay open.

Well...do you loose power to the solenoid? Sounds like in your first post you loose power to the white wire? If you ARE loosing power, i'd say your solenoid is good....a "Common" problem on these machines is the Time Delay Module...which I belive is what controls the Shutoff solenoid

I have had different problems with it and am wondering if they are related. Originally it would start but took some time to reach full throttle. I thought this was normal and meant the motor was not warmed up yet.

Both my F935 and the F925 I just picked up run a little rough when first started...I think the Yanmar 3TN72 doesnt like to be cold...

I mow fine for a while and then the PTO shuts off. I then move the PTO switch off and on and the PTO engages normal for a while then shuts off again.

Hmm...Do you have a PTO Switch or Lever? My F935 is an older model and seriously speaking I replace the PTO/Neutral safety switch once every other year... Now that I am typing, Maybe the problem isnt your cutoff but the PTO/Neutral Safety switch...I know one of the symptoms of my PTO switch going bad (I keep a spare in stock ) is she wont start...fiddle with the PTO lever and presto, she fires up...

Mowing normal and the engines tries to die? To keep the engine from dying I return the foot pedals to neutral and the engine idles? If I give it forward or reverse it dies.

Hmm...Sounds like she's lacking power...fuel system in good shape? Filter, lines, etc... Problem i had with mine was the fuel lines IN the fuel tank were rotted out so when in motion with a 1/2 tank or less of Diesel, she'd suck air...

I am also wondering if these problems are related to the interlock (safety system?eat switch, brake switch, etc.).

Cant really help you there, ALL safety interlock crap has been removed from my machines. The ONLY safety I left was the PTO Neutral safety switch..because thats pretty much the only one I belive in...

 

[zzvyb6]

Cold weather roughness and hard starting were cured on mine when I replaced the 3 glow plugs. I will look up in the service guide what other possibilities there are for solutions to your problem(s). Water in fuel is another good possibility. You can drain the water separater via the tap valve in the filter module. On mine, the lever at the switch by the pto brake was bent just enough to often release the pto. Wacked with a hammer solve my only issue with the machine so far. While you are at it, check the driveshaft isolator for cracked/broken elements...

 

[jd3020u]

I had a 97 F935 with 1800 hrs on it. When I first bought it, it was hard to start and low on power. I think I was cleaning the engine up or something and found that over time, enough slop had developed in the linkage between the solenoid and the pump that it would no longer open the shut off all the way. A simple adjustment had me starting on the first crank every time. I don't know if this will help your case but I have checked every tractor I use since then.

Tim

 

[digger70]

:mur:I have just bought a f935 and is doing the same thing running with the foot petal deal and pto engagement,The pto engages and works sometimes and another time the pto starts by itself with nobody on the machine, Scared the s*#t out of me. Does anyone have a wiring diagram or manual for this to share? I have no manuals for this yet.

I also have been under the machine and found the rubber isolator is cracked badly, Is this not helping the problem? Not using this machine parked in garage. Stumped any help is appreciated, Thanks John