961 starting system question

FrankS

Member
Working on a friends 961 Ford serial # 2461 and have a couple questions. He replaced the 6 volt battery and hooked it negative ground. Is this tractor supported to be positive ground? IT manual shows 6 volt positive and 12 volt negative but covers a lot of models.

The tractor won"t turn over unless I jump a hot wire to one of the small terminals on the solenoid and a ground to the other. The starter then turns it over just fine. Therefore I assume the solenoid is OK. However, when I remove either of the jumpers it won"t turn over with the key on and the push button switch depressed. The solenoid and wires had been removed by my friend so I"m not sure which goes where. I assume the single red wire from the push button switch goes to the solenoid S terminal. There is continuity from the solenoid end of the red wire to a ground when the push button is pressed so I assume that side is OK. The "I" terminal would then get the red and white wires. I assume the red wire is from the keyed switch. With only the key on should I get 6 volts at the red wire? Also does it matter which large posts the battery and starter cables go to? The white wire runs to the coil and there is continuity. I assume this wire has to be connected for the tractor to run. I rigged a connector so that the white wire was connected and yet allowed me to hook a jumper hoping to get it running and into the shop. It turned over with the jumper but wouldn"t start. Help will be appreciated.
 
Couple of things-

Install the battery correctly, positive to ground.
One of the small solenoid posts should be wired to the starter switch which should provide a ground when pressed. Be sure the tractor is in neutral.
The other small solenoid post should be wired to the side of the terminal block that has -6V when the key switch is ON along with the "-" side of the coil and also the wire to the fuel gauge thru a fuse.
It does not matter which large post is which, but one should have a large wire directly to Batt "-" and a small wire that goes to the voltage regulator "B" terminal. The other large post should have a large wire going only to the starter.
Set up this way it should start and run, if not then post back and let us know what you find. If it does run, I suggest you check to be sure the battery is charging properly with a voltmeter. -Will
 
Thanks Will. I"ll switch the battery to positive ground and check the voltage to the solenoid and to the coil. Didn"t have my voltmeter with me but the fuel guage has been replaced with a voltmeter and it reads 6 volts plus. What doesn"t make sense is that it turns over with two jumpers but not when either is removed.
 
(quoted from post at 00:10:08 07/30/13) Thanks Will. I"ll switch the battery to positive ground and check the voltage to the solenoid and to the coil. Didn"t have my voltmeter with me but the fuel guage has been replaced with a voltmeter and it reads 6 volts plus. What doesn"t make sense is that it turns over with two jumpers but not when either is removed.
ou mention 2 wires on the I terminal......this is not according to schematic diagram. You mention no wires other than battery cable on the large solenoid stud. This suggest to me that one of the two on I actually belongs on the battery side large stud. This would explain your conditions, as without wire on battery side large stud, there is no battery power to ign switch or anything else other than starter. That does not explain reading on dash voltmeter, but I do not know where it is connected?
 
There is another wire on the large solenoid stud.
The two wires on the "I" terminal are joined inside
the rubber connector and thus appear to be factory.
There have been changes made such as replacing the
fuel gauge with a voltmeter and it has an alternator
instead of a generator. However, the tractor started
and ran just fine for over a year. It suddenly went
dead.
 
(quoted from post at 10:21:40 07/30/13) There is another wire on the large solenoid stud.
The two wires on the "I" terminal are joined inside
the rubber connector and thus appear to be factory.
There have been changes made such as replacing the
fuel gauge with a voltmeter and it has an alternator
instead of a generator. However, the tractor started
and ran just fine for over a year. It suddenly went
dead.
ounds like more here than "suddenly went dead". " The solenoid and wires had been removed by my friend so I"m not sure which goes where. " Since the diagram shows only one, not 2 wires on that small solenoid terminal, I would find out where the other end of each wire is connected.
 
It has an alternator? This changes things because it should have also been converted to 12V negative ground. Are you sure it had been running for a year with a 6V battery? -Will
 
My friend replaced the original battery with a new 6 volt so I"m not sure what it was. However, the tractor turns over just fine with the new battery and two jumpers on the small solenoid terminals - one hot and one ground. But not when I pull either jumper. I"m going to try jumping across the solenoid large posts and verify there is 6 volts coming from the keyed switch.
 
So, in summation, we are blind, working on something where we haven't a clue as to what modifications have been made & thus no way of knowing how it is currently wired. Two wires where one belongs, alternator, positive or negative ground, 6v or 12v? Outcome? Been to Vegas lately? :roll:
 
Right. Freewheelin, seems like the best thing would
be to trace the wiring out, draw a wiring diagram as
it now is, (maybe print and mark up the one JMOR
already posted) take a picture of that and attach it
to a new post, then maybe we can suggest a way to
sort it out correctly. -Will
 

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