Starter keeps cranking

Old 06-21-07, 04:16 PM
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Exclamation Starter keeps cranking

This isn't a car problem, but - We have a JLG bucket lift with a Ford 2.5L 4cyl. ('88 or '89) Last year, we had a problem with the unit not starting. Got the telltale click, click, click sound. Service tech determined it to be the solenoid. Said part was replaced. Unit started fine. After about 20 starts, the starter would not disengage after cranking. - even after key switch was turned off. The only way to stop it was remove battery cable.

Solenoid - and this time a starter - were replaced to the tune of $500.
Unit ran great for about 6 mos. Then same problem. Starter would remain engaged. Sometimes tapping the solenoid would help. Finally found out that by shorting across the solenoid, it would disengage. Solenoid again replaced.

Monday of this week-- same thing. Burnt the starter out. Another $500.
Today, after only 3 starts on the new solenoid and starter, it did the same thing. It does not seem to matter if the unit is cold, or has been running all day. The solenoid is the remote type. - and they are using Mastercraft parts.

Anyway, the repair techs are all baffled. Even the "expert" techs at JLG are scratching their heads. I highly doubt that we have had this many bad solenoids in a row. What could be causing this thing to stay engaged? Any ideas would be greatly appreciated. I don't seem to be able to find a priest willing to perform an excorcism on a boom lift....

Old 06-21-07, 04:21 PM
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Sounds like the solenoid is getting too much juice. Check for proper voltage coming from the alternator/voltage regulator.
Old 06-21-07, 04:25 PM
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Too much juice...

So pretty much anything over 14.3 v or so is way too much...?
Would this be the case even if the unit does not start??
Often times, the unit will not start on the first try and the solenoid stays engaged... Could the alternator be charging that much at less than 500 rpm??

Will check it out.
Old 06-21-07, 04:57 PM
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Have you broken open any of the old solenoids to see if contacts inside are getting burned and/or to see why contacts may not be retracting when key is off?

Also, without over analyzing this, make sure everything is grounded properly to create proper loop with negative on battery, in case there is some ground issue and some redirected pathway is creating a weird electrical disturbance or load where it should not be.
Old 06-21-07, 05:30 PM
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There is a chance your starter relay isn't handling the amount of amps the starter is pulling through it. The contacts are probably getting fried and sticking together.

Since you have the remotes on it and having a hard time getting it fixed, I would either go to a heavier relay (Freightliner uses about the same thing on the '99 112 models) or wire a pair of them together to handle the starter.

I'd have to admit, though, that size engine shouldn't be having problems with starter draw if everything is working right.

Hope this helps,

Old 06-21-07, 05:40 PM
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sounds like the other guys are on the right track.

I would suggest and OEM solenoid. Sometimes aftermarket parts just aren;t what they pretend to be.
Old 06-21-07, 07:58 PM
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Question Huh?

Just got back from the shop. Started the unit - (amazingly) and checked the output of the alternator...fluctuates between 13.9 and 14.4 volts..depending on the load. (lift going up or down, no load, etc.)

Cracked the old sol. open...surprise surprise..the contacts were black and pitted. - looked like the tip of a mig welder when you get too close to your work.

This thing is starting to really freak me out.
I guess I'll explain what I've found out to the tech guru in the a.m.

**Correction - using Motorcraft O.E.M. parts not Mastercraft.

Thanks for the ideas!
Old 06-22-07, 06:30 AM
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Should sounds like a solenoid problem. All lifts I have been around have push button or toggle switches to activate the solenoid, check to make sure these switch are not sticking and staying in the closed position. Since it does'nt do this every time, to be safe I would change start switches because they might show good when tested, but stick on occasion when in use.
Old 06-22-07, 06:35 AM
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Another possibility on this thing is the hydraulics. I'm reasonably sure you would have live hydraulics on it. You may have a hydraulic valve holding pressure back on the pump causing the starter having to overwork to spin the motor.

It could be pressure release valve or a control valve.

Just a thought,

Good luck.
Old 06-22-07, 07:28 AM
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would suspect the battery or bad connections from the battery your charging voltage is normal usually when a ford starter solenoid stays engaged it is due to low battery voltage you should probably have the battery load tested.
Old 06-22-07, 07:47 AM
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Add some lights for diagnostics

I would wire a light With 2 wires coming from it. One red wire and one black wire. The light would be near the operator where they can see if it is lit.
The red wire would be connected to the large starter cable going out of the solenoid to the starter. The black wire from the light to the battery negative or a good ground.
This wire should only be lit when cranking the engine over with the switch.
If it lights any over time then you know the solenoid has closed for some strange reason.

I would also add a second light. One red wire and one black wire. The light would be near the operator where they can see if it is lit.
With this light the red wire would go to the wire that activates the solenoid from the start switch. The black wire would go to the negative battery post or a good ground. This light should be off and only come on when the start switch is closed. If it comes on any other time then there is power going to the solenoid telling it to open

There sould be 9 volts or so available when cranking so an automotive light bulb 1156 or 1157 should light bright enough while cranking to give an indication. Any low wattage bulb for that matter. It don't have to be expensive. Just some parts you have around the shop.

This bucket lift dosent have a name of "Christine" does it?

I would put a wing nut on the negative to frame connection so I could disconnect it there if it did keep the starter running.
Pulling the battery cables off a working battery if very dangerous being that it will be emitting hydrogen gas.
If this is impractical then maybe a second solonoid on the negative as backup could work
Hydrogen and sulfuric acid and flying debris could get someone killed.
Please work safely and go home the same way you came in.

Last edited by frankiee; 06-22-07 at 07:54 AM. Reason: Add safety concern
Old 02-24-08, 03:38 PM
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Replace the Relays

We had the same thing happen to a Freightliner FL60. The starter wouldn't disengage and burnt up the starter/solenoids. Replaced the starter and no change, then the batteries and no change, and next the ignition switch. Finally the truck cranked like a brand new one when we replaced the relays. It also stopped the draw on the batteries. Something to try.

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