876 shut off won't start

[cafoose 3,464]

I was spreading stone today with the dozer blade on my 876 and it shut off and would not start. I converted it to a solenoid and did away with the high amperage ignition switch. I got 13 volts at the terminal on the solenoid from the battery. I have almost no voltage to the terminal from the solenoid to the starter/generator. When I disconnect the terminal on the solenoid to the starter/generator I get 13 volts to the terminal on the solenoid. The wire is good from the starter/generator to the solenoid. All connections are clean and tight. I believe the starter/generator went bad because everything leading up to it is good. tight, and clean. I had the tractor 25 years and did nothing to the starter/generator and it looked like nobody else did anything to it either before I got the tractor around 1992 or 1993.

[ZXT 2,401]

So you're saying when connected, the solenoid trigger wire has little voltage but has 13v when disconnected? Sounds to me like a bad connection somewhere - you have voltage but no amperage. Did you try jumping across the solenoid to see if it would crank? 

Edited October 27, 2019 by ZXT

[cafoose 3,464]

12 minutes ago, ZXT said:

So you're saying when connected, the solenoid trigger wire has little voltage but has 13v when disconnected? Sounds to me like a bad connection somewhere - you have voltage but no amperage. Did you try jumping across the solenoid to see if it would crank? 

No, the little terminal on the solenoid from the ignition switch only has 13 volts when the key is turned to the start position, it has zero volts in any other position which is normal. In start position I can hear the solenoid click and with all the wires connected I get 13 volts at the big terminal connected to the battery and less than 5 volts at the solenoid terminal connected to the starter/generator. When I disconnect the wire to the starter/generator at the solenoid and turn the key to start I get 13 volts to all 3 terminals. As soon as I connect the starter/generator to the solenoid I get less than 5 volts at the starter side of the solenoid again. All connections are clean and tight. I'm thinking maybe brushes? It does not crank jumping the big terminals together. I tried that first.

Edited October 27, 2019 by cafoose

[ZXT 2,401]

1 minute ago, cafoose said:

No, the little terminal on the solenoid from the ignition switch only has 13 volts when the key is turned to the start position, it has zero volts in any other position which is normal. In start position I can hear the solenoid click and with all the wires connected I get 13 volts at the big terminal connected to the battery and less than 5 volts at the solenoid terminal connected to the starter/generator. When I disconnect the wire to the starter/generator at the solenoid and turn the key to start I get 13 volts to all 3 terminals. As soon as I connect the starter/generator to the solenoid I get less than 5 volts at the starter side of the solenoid again. All connections are clean and tight. I'm thinking maybe brushes?

Could very well be, but it seems odd that it died while running - brushes shouldn't cause that. Have you tried rotating the engine over by hand and then attempting to crank it? Sometimes when brushes are on their way out you can re-seat them temporarily by doing that.

[cafoose 3,464]

1 minute ago, ZXT said:

Could very well be, but it seems odd that it died while running - brushes shouldn't cause that. Have you tried rotating the engine over by hand and then attempting to crank it? Sometimes when brushes are on their way out you can re-seat them temporarily by doing that.

No I did not it started raining and I just left it sit for now. I probably should have tried turning it by hand before going in. I figured the brushes wouldn't cause it to die while running. I was pushing heavy stone and it stalled on its own like normally happens when I push it too hard. Most times I back off when it does that and it speeds back up to normal but occasionally I don't back off soon enough and it stalls. I think that's why it stalled the last time and the starter wouldn't let me start it back up.

[adsm08 3,435]

You have a weak connection inside the solenoid, and you are dropping almost 8 volts across it.

 

Voltage drops across a load. Resistance, or a weak connection, can become a load. With the S/G unit disconnected the open circuit you created after the solenoid is a huge load, and so no voltage drops across whatever resistance is inside the solenoid. In automotive electrical we call this "Open circuit voltage" and it is really only useful for seeing how much voltage is being applied to the circuit.

 

When you have the S/G unit hooked up you are load testing the circuit, and essentially doing a voltage drop test on the start circuit. Since you have an open circuit voltage of 13, a loaded voltage of 5, you are dropping nearly 8 volts across that solenoid, or one of your battery cables.

 

Take a screwdriver and touch it to both large terminals. If the solenoid is the issue the engine will crank.

[cafoose 3,464]

9 minutes ago, adsm08 said:

Take a screwdriver and touch it to both large terminals. If the solenoid is the issue the engine will crank.

 

52 minutes ago, cafoose said:

It does not crank jumping the big terminals together. I tried that first.

 

[adsm08 3,435]

7 hours ago, cafoose said:

 

 

 

OK, I missed that.

 

Next test would be to take a pair of jumper cables and go between the B+ and the A terminal.

[Tractorhead 9,212]

Take a closer look at your Ground wiring also.

clean connection and tighten bolts.

are the Cables fit tightly in the connectors.

no corrosion visible there?

 

to check out if the S/G itself was faulty, i would test it by a clamp Ammeter if you have.

Did you try follow:

 

connect a Voltmeter directly on the incoming Terminal of Solenoid ( thick terminal).

check if Voltage drops while cranking.

if it doesn‘t, try with 2 Jumpercables follow:

 

connect the Batteryground to Starterground

connect the battery positive to solenoid out ( thick terminal).

the starter shall run.

if not, it seems the brushes are too weak or gone.

 

 

Edited October 27, 2019 by Tractorhead

[953 nut 60,710]

9 hours ago, cafoose said:

As soon as I connect the starter/generator to the solenoid I get less than 5 volts at the starter side of the solenoid again.

sounds like the solenoid itself is the problem. With no load the contacts are able to pass full voltage, but with a load they are unable to. Have you used a screw driver or pliers to jumper the two large terminals of the solenoid?

[cafoose 3,464]

1 hour ago, 953 nut said:

sounds like the solenoid itself is the problem. With no load the contacts are able to pass full voltage, but with a load they are unable to. Have you used a screw driver or pliers to jumper the two large terminals of the solenoid?

 

11 hours ago, cafoose said:

It does not crank jumping the big terminals together. I tried that first.

 

[Achto 29,504]

Does your battery voltage drop as well when you try to start it? If it does then I would guess the the SG is the issue. There is also a chance that the winding's have shorted out. It this is the case then you will need to do a full rebuild.

 

https://isavetractors.com/rebuild-kit-for-delco-remy-starter-generators/

You may have to have the armature turned if it is in bad shape if you choose to rebuild.

or

http://www.psep.biz/store/kohler_starter_motors.htm

Edited October 27, 2019 by Achto

[pfrederi 18,771]

Have you tried a Heavy jumper from Battery + to the A terminal on the generator??

[cafoose 3,464]

It's raining now and it's sitting outside. It's supposed to stop raining after 1pm then I will try some of these suggestions. If all else fails I may put a spare s/g I have on it and tear the bad one apart.

[squonk 44,036]

If your cables are original, they could be the problem. I have seen them look good but peel the insulation off and they will be a green spot somewhere. and an ohmmeter will do no good. A bad cable will do  the exact same voltage drop across the solenoid with a load on it.

[pfrederi 18,771]

18 minutes ago, cafoose said:

It's raining now and it's sitting outside. It's supposed to stop raining after 1pm then I will try some of these suggestions. If all else fails I may put a spare s/g I have on it and tear the bad one apart.

 

 

Wet Horses are not Happy Horses...

[cafoose 3,464]

21 minutes ago, pfrederi said:

 

 

Wet Horses are not Happy Horses...

[953 nut 60,710]

9 hours ago, squonk said:

I have seen them look good but peel the insulation off and they will be a green spot somewhere. and an ohmmeter will do no good. A bad cable will do  the exact same voltage drop

Good point Mike, If you hold the starter a few seconds and feel a warm spot on either the Ground, Starter or Battery Cables you have found the culprit.

[cafoose 3,464]

I swapped out the S/G with another one and it cranked over but stopped cranking before it fired off just like before Then I took a battery I had on a battery tender that showed a green light and put that in. Still no cranking Then I put on all new battery cables and no difference  I took my truck and jumped the battery and it fired right off  I finished spreading the stone and shut it off now it will not start without a jump  This is inside the old S/G 

[pfrederi 18,771]

Green light on a battery minder doesn't necessarily mean the battery has enough capacity to crank very long.  Just means it has reached 12.6 volts.  Really need to do a load test on the batteries. (They will show 12.6 then when you hit the load it drops precipitously) ... Also did you try feeding the A terminal directly from a good battery + post???

[cafoose 3,464]

1 hour ago, pfrederi said:

Green light on a battery minder doesn't necessarily mean the battery has enough capacity to crank very long.  Just means it has reached 12.6 volts.  Really need to do a load test on the batteries. (They will show 12.6 then when you hit the load it drops precipitously) ... Also did you try feeding the A terminal directly from a good battery + post???

Where is the A terminal, is it on the starter? If it's the terminal that the heavy battery cable goes to from the solenoid yes I did feed it directly with no difference. I hooked a volt meter to the battery and turned the key to start position and the voltage dropped from 13V to around 5V. Maybe I should load test the battery. How can I do that?

[953 nut 60,710]

1 hour ago, cafoose said:

should load test the battery. How can I do that?

Take it to your favorite auto parts store, they will load test it for free.

[cafoose 3,464]

51 minutes ago, 953 nut said:

Take it to your favorite auto parts store, they will load test it for free.

[pfrederi 18,771]

A drop to anything below 9 volts says it is toast.  So many times a bad battery is the cause of electrical problems...

[cafoose 3,464]

22 hours ago, 953 nut said:

Take it to your favorite auto parts store, they will load test it for free.

I just dropped off my batteries to be load tested we will see what happens