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Push/pull stop solenoid.

007

Senior Member
Joined
Dec 28, 2016
Messages
280
Location
Australia
Hi antpoo,
You are correct.
Unless the starter motor was engaged for an extraordinary amount of time the starter and its solenoid will be fine.
It will be the small relay near the starter with the 5 terminals which had the fault current applied to the relay contacts.
If you bridge out the two terminals on the right shown in your circuit diagram the starter motor should engage.
Cheers
 

antpoo

Well-Known Member
Joined
Dec 7, 2014
Messages
158
Location
australia
IMG_0398.JPG Hello all

Problem solved, but it was worst case scenario. Starter motor $700 installed.



I tried to bridge starter motor and got a load of sparks only, as in a direct short.

Removed starter and all the copper bits fell out and the rest was black.

Here is how it happened.

Ignition cranking too long over heated stop solenoid and melted insulating wires, they now were touching each other and one of them (the pull) was a direct link to the starter solenoid!

It seems that if I had only unplugged and removed the stop solenoid from the circuit I would be saved, but instead for two hours the stop solenoid pull wire was touching the others and gave the Starter motor a crank signal, and it proceed to burn itself to pieces. See pic below.

Thank you for your help, I hope this thread serves to inform others unfortunate enough to be in similar situation.
 
Last edited:

007

Senior Member
Joined
Dec 28, 2016
Messages
280
Location
Australia
Good to hear you have it under control.
Just as a by the way the damage shown in the picture of the starter is more than just being energized.
The starter was not operating electrically with no commutator or brushes.
The only way normally the commutator flyers to pieces from over revs and destroys all the brush boxes like that is the pinion being stuck in mesh with the ring gear with the motor running and that damage probably happened in about 30seconds not hours.
There would have been a loud screaming noise coming from your starter during this process until the pinion clutch seized and over revved the armature.
Im not sure i agree with your theory as if the starter was given a crank signal the inhibit relay would not have engaged the starter with the engine running.
I think more likely the starter solenoid became overheated and locked in keeping the pinion engaged and also sending power to the stop pull in circuit and it all went down hill from there.
Any way at least you are away again.
Cheers.
 

antpoo

Well-Known Member
Joined
Dec 7, 2014
Messages
158
Location
australia
Good to hear you have it under control.
Just as a by the way the damage shown in the picture of the starter is more than just being energized.
The starter was not operating electrically with no commutator or brushes.
The only way normally the commutator flyers to pieces from over revs and destroys all the brush boxes like that is the pinion being stuck in mesh with the ring gear with the motor running and that damage probably happened in about 30seconds not hours.
There would have been a loud screaming noise coming from your starter during this process until the pinion clutch seized and over revved the armature.
Im not sure i agree with your theory as if the starter was given a crank signal the inhibit relay would not have engaged the starter with the engine running.
I think more likely the starter solenoid became overheated and locked in keeping the pinion engaged and also sending power to the stop pull in circuit and it all went down hill from there.
Any way at least you are away again.
Cheers.


Hi 007,

After the wires burnt, it actually started normally and I operated it for nearly two hours before shutting down. Thus, it did indeed stick in the ring gear and tear to pieces, but because I was far away in the cab with the engine running I did not hear this. Because the pull wire from stop solenoid had a direct link to the starter, the relay that protects from secondary over crank was bypassed when it became energised when it touched the bare push wire and the stop solenoid basically became a make shift fuse for the starter itself. It engaged starter, and destroyed, and I did not hear a thing.

So the lesson learnt, if you overcrank and melt wires on the stop solenoid, do not risk starting machine again, even if it starts, because the risk is too great that the wires will short each other and energise starter motor while engine running. There is simply no protection available for if this happens.

Thank again.
 
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