901 Ford powermaster starting problems?? wiring ??

[Nathan Jones]

Having a problem wiht my 90 pwoermaster maybe you can help...(it is a 12V convert)
Will not start. No power to the starter. Using a test light, have power to the battery side of the starter solenoid (same as a car), and when you turn the key on there is pwoer to the "I" terminal on the solenoid. HIt the foot starter button, and nothing; no pwoer goes to the starter cable terminal side of the solenoid. I firts thought the solenoid went bad, so i took one off another car so I know it works. Still nothing. I thought perhaps the starter button went bad and didnt complete a ground. Using a continuity tester, i tested the button, and it done make a ground. Not the starter, checked that, it is just not sending power over to the starter cable, but it is not the solenoid. ANy ideas??????

 

[Dean]

Nathan:

Did the starter ever work using the original starter switch after the 12V conversion?

If not, it is mis wired or the incorrect solenoid was used.

If so, the solenoid has failed or is not being energized by the conversion circuitry.

Dean

 

[petra79]

Sounds exactly like what I just fixed on my 861 yesterday. The ground cable was all green inside the casing. Looked good on the outside. I disconnected the B- at the tractor and using the test light got no power to the end of it. Just a thought.

 

[john in la]

You have the problem listed in your post.
Now all you need to do is read it and find the problem.


Hint....... so i took one off another car

A car relay will not work on your tractor if you followed my diagram.

To see if I am correct try these 2 test.......

1) you say you have power at the I term. Do you have power at the small S terminal also. I am betting NO.

2) take off both small wires (I and S terminal) now with a jumper wire touch battery power to the S terminal. Does it try to crank now. I am betting YES.

So if I am right so far you need to buy the proper starter relay.

 

[Nathan Jones]

thanks for al the help. I will try that john. Here ar e a few more details.
1) It was already wired like this and working. It just quit; I assumed the solenoid (or is it the relay) quit

2) The solenoid looks identical to the one use on older for dcars. Are they different? What hould I aks for at the parts store?

 

[Nathan Jones]

Bump... look up at my reply

 

[Nathan Jones]

the part i am talking about; is it a starter solenoid or a starter relay? It is the same as the peice on the firewall on a 60s ford car. What should I ask for at the parts store?

 

[john in la]

Sorry I was at work but let me answer your question.........

If it was working before and quit your relay way have went south. Replacing it with one from a car or truck does no good because while they look the same they are wired different,

The relay from a car/truck is a grounding relay and your tractor uses a ground isolated relay.
In the car relay the S post is hook to the medal part where the bolts hook. In the tractor relay the S post is hooked to the I post.

So when you check the relay you have power coming from the key to either post S or I. The power travles threw the relay and out the other post where the starter button wire hooks. Pushing the starter button completes the circuit allowing electricity to flow making the relay trip and the starter to turn.

So you need a 12 volt ground isolating relay. Some part # are ...........
Ford....311006.....$27.02
Napa....ST542.......$31.49
O Reilly......S103....$27.99
Advance Auto....S103....$16.29

S103 is a BWD # and most any place will have this or can cross it to something they do carry.

The part is technically a RELAY but most people know them as a SOLENOID. Without getting into the technical difference I choose to type relay because I have a hard time spelling solenoid.
When buying the part ask for a starter solenoid because that is the term most use and the kids at the parts counter may not even know it is really a relay.