NAA Starting Problem

[therm8]

This is my first post. I've searched this forum for a couple hours looking for a related problem, but found nothing so here goes.

Tractor ran just fine about 4 days ago, when I moved it out to the road to post a 4 sale sign on it. It is a 6 volt system. Have a fellow coming to look at it in a couple days so I thought I better go start it up just to make sure... Turn on key, engage clutch, in neutral, push thumb switch and nothing. Zero reaction. First thought is key switch, so I pulled the wires and shorted them with some copper wire, and still nothing. Best I can tell the starter is pretty old, the coil was replaced when the engine was rebuilt in '08 (so I was told). I did change the battery early this year, and the only thing I could get my hands on local at the time was an 8 volt battery, but I've heard of people running 8 volt batteries on hard starters before so I figured it would work. Any direction would be appreciated. I hate electrical problems...

Thanks,
Mike

Edit:

Some electrical measurements:

Continuity across key switch when closed : 2 ohms
Battery volts: about 7volts
Voltage across relay or solenoid (not sure: positive battery cable connects to it) (thumb switch not pushed): 7volts
Continuity negative battery terminal to thumb switch terminal (not pushed): open
Continuity negative battery terminal to thumb switch terminal (pushed): 10-13 ohms

 

[jeff pk]

I'm no expert, but the first thing I'd do is check that battery cables are making good clean contact and that the starter is grounding to the engine properly. If the NAA is like other Fords, the starter will ground itself to the housing it's bolted to, and if this gets corroded it will not work...

 

[DaveOmak]

If everything is original, there is a button on the solenoid.... push it and the starter should turn over.... The engine shouldn't start until the key is turned on.. The "thumb switch", on top of the tranny connects the ground side of the electrical circuit... Check the battery voltage when the thumb switch is depressed... see what happens...

 

[Soundguy]

8v batterys don't charge up well with 6v generators.

leaves you with a dead 8v battery?

i wonder what makes people do stuff like that?

would you put diesel in your fuel tank? they both burn??


in any event. charge the 8v battery (HMM.. now how you gonna do that? )

check bat cables and ground strap locations.

once you have a charged bat to work with ( yes.. 12v will work for testing ...truck = donor ) then see what you got. small wire from thumb switch grounds lil 3rd wire on solenoid to energize it. or have you changed out the oem solenoid?


need mroe details.

 

[therm8]

Thanks for the replies folks. Battery is at 7.1V.

I have 7V across solenoid with thumb switch not pressed. When pressed voltage across solenoid drops to 1V. No sound from solenoid, which makes me suspect it. Barring anything else, it is a $15 part, I will run to town next day I'm off and pick one up. Will check the starter motor ground too. Wire to case should do that correct?

I realize the 8V battery is not ideal, but the day I really needed the tractor it was all I could do on short notice. But since it is at 7V it'll suffice for the current troubleshooting.

Key switch and thumb switch are both good. Next likely problem would seem to be solenoid as far as I can tell.

 

[Soundguy]

7.1v on an 8v battery is dead... deader than dead.

easy way to test the solenoid is to simply take it off. apply ground to the small post and then hot to the battery post. it will either pull in or not.

 

[DaveOmak]

I have 7V across solenoid with thumb switch not pressed. When pressed voltage across solenoid drops to 1V.

Soundguy is right...... You have a dead battery.... Under load, the battery should read 8+ volts....