Starter will not quit cranking when you let off of the key

000127

New User
I have a JD 500c backhoe starter has been rebuilt and will not disengage when I let off of the key it has new battery and terminals
 
Do you have the Delco or Nippo-Denso starter motor? If a Delco, I would suspect the contacts are stuck together in the solenoid that is
bolted to the starter.
 
On one like that it could be the solenoid or the key switch. Do some simple trouble shooting. Take the wire loose from the solenoid the small one. Now hold it in place while spinning it over to start. Once it starts remove the wire and if the start stops spinning then the switch is bad. If it does not stop the solenoid is bad
 
I've had that happen before. Many times it was because the contacts in the starter solenoid (subject to what kind you have) got stuck/burned/welded together. Perhaps the starter got rebuilt but NOT the solenoid????

If the start switch (depending on the switch and system) somehow maintained electrical contact in the START position that could keep the starter/solenoid engaged. That was rare in my experience...?..

Its possible to use some jumpers to duplicate the start switch function (to send voltage down to solenoid) and/or do similar to jump hot voltage direct to the solenoids activation terminal for troubleshooting.

Typically I saw that happen most often in either extreme cold weather (starter drawing high current) or the battery was weak or there was a bad cable or connection or poor ground.

John T
 
If this is a Delco or any starter with the solenoid on top that pulls the plunger in, the problem is likely in the starter.

What happens, the solenoid pulls the drive into the flywheel, the spiral on the shaft takes over and extends the drive fully out to the end of the travel, against the thrust washer in the end of the nose cone.

That in turn pushes the plunger fully into the solenoid, and holds the button that closes the contacts in, keeping the starter engaged. Chances are once the engine fires it will kick the drive out, stopping the starter.

But that's not acceptable. The rebuilder either left the thrust washer out at the end of the drive, the nose cone is chewed away where the thrust washer rides, the plunger fork is in backward, wrong plunger, wrong drive... Something is mechanically not right.

To prove it is in the starter, disconnect the small wire from the solenoid that energizes the starter. Jump from the battery post to the small post, see if the starter continues to crank with the wire disconnected.
 
You don't say what you do to eventually get the starter to stop turning. Disconnect battery? Thump it with a hammer? I think this would go a long ways in diagnosing your problem.
 
Try what Old suggested. It's so easy to do. Also it could be as simple as the key switch not returning from the start position if start is in the key switch and not a separate button.
 
(quoted from post at 12:54:30 09/14/19) Do you have the Delco or Nippo-Denso starter motor? If a Delco, I would suspect the contacts are stuck together in the solenoid that is
bolted to the starter.

Ditto if Delco starter. I've seen washer inside solenoid cap stuck to contacts on several different occasions.
 
Seen that many times when I was auto mechanic Steve at advance is right on. thrust washer and snap ring
 
I had this problem on the 6.2 diesel GMC pickup I owned. If the batteries got weak it would weld the solenoid in
the engaged position. Easy enough to cure. Wire the main wire going to the starter solenoid through a Ford style
solenoid. Then run a jumper from the main wire post on the starter and connect it the G M solenoid small wire post
so that when the Ford Style solenoid sends current to the starter it will activate the solenoid on top of the
starter and when you let go of the key, the Ford style solenoid stops the current flow to the starter.
I burned up a couple of the 40 MT series starters before I hit on this idea.
This happened to the wife one day and all she could think to do was open the hood and scream for me..


Gene Davis Tennille, Ga.
 
I had a similar problem when I had the
starter on my 4020 rebuilt. The starter
would bench test okay but when installed on
the tractor it would stay in gauge until
the battery was disconnected. My fix was
turn the yoke around between the solenoid
and the bendix. Your starter maybe
assemble wrong.
 

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