John Deere HST 4200 not starting

[tp71malibu]

I have read the past threads on JD not starting and how it could be a thermistor or solenoid. I replaced the solenoid ($175!) and the tractor started right away and has been fine until a couple of days ago and the same thing happened. It cranks but just does not seem to want to fire. I have checked all the obvious proplems (gas in tank, etc). One thing that is different is it got really cold here. I do have a glow plug and it seems to work fine. Any other ideas? This is my first post but have enjoyed the site for a couple years. Thanks!

 

[Willl]

I'll take a guess and say your 'new' solenoid is shot. And I'll also guess your 'timer' would be to blame.

Todays solenoids actually have 2 solenoid coils built into one. When you turn the key to start, it activates the larger of the 2 coils in the solenoid to pull in the plunger. After a few seconds, your 'timer' will switch to the smaller coil.

If your timer don't switch over, running the larger coil continually will smoke it.

Pull your solenoid out and see if it will fire up. To shut it down, you'll have to stuff the solenoid back in.

 

[JD755]

Discussions in the past have talked a lot about the dual coil solenoid. I don't remember the specs being shown before. These give you an idea of why the pull-in coil should only get power for a moment. That's a lot of current to that little solenoid! This is from the CTM3 manual.

Fuel Shutoff Solenoid
Maximum Pull-in Amperage . . . . . . . . . . . . . . . . . . . . . 50 Amps for 1/2 second
Maximum Hold-In Amperage . . . . . . . . . . . . . . . . . . . . 1 amp continuous

 

[Egon]

On your tractor you may air pre heaters rather than a glow plug.

Do you hear the solenoid click when you turn the key?

 

[tp71malibu]

Thanks for the replys! I do hear a click when I turn the key, that why I am wondering if it is something other than the solonoid. I don't have a meter so I can't test the circuits. I am suspecting that if I take the solenoid back off and try to start it, it will start up but then what is the problem? Is it the solenoid that is the issue again?

 

[JD755]

You can look at the solenoid to see if it is working. It will pull in the linkage when you start, and then stay in as long as the key is ON. If it pulls in, then the high current coil is working, but if it will not stay in then the holding coil is the problem. Could be wiring, connectors, or the coil. If it pulls in and stays in then your problem is elsewhere.

 

[hawkeye08]

Thanks for the replys! I do hear a click when I turn the key, that why I am wondering if it is something other than the solonoid. I don't have a meter so I can't test the circuits. I am suspecting that if I take the solenoid back off and try to start it, it will start up but then what is the problem? Is it the solenoid that is the issue again?

You can get a cheap meter at HF for less than $10.

 

[kennyd]

You can get a cheap meter at HF for less than $10.

Exactly. There is no way you can trouble shoot this without a meter unless you just replace parts hoping to fix it.

 

[Egon]

Any way to check and see if there is any fuel past the solenoid?

 

[lekwyo]

I have a 4200 and I have experienced the same problem,usually associated with pushing the key in to pre-heat before starting. The engine will crank but not fire. I have switched out the thermistor with no change. What I have found that always works is to switch out the relays in the fuse box on the console. It seems the2nd relay from the top, middle row is the culprit. I have never understood why this would work but switching relays has always worked to get the tractor started. Certainly worth a try and simpler than pulling the fuel solenoid.