Electrical (Solenoid) Gremlins

[MingOK]

I finally got my 8N back together after engine rebuild (12v conversion, front dist.) Installed new solenoid, key switch and wiring harness (per JD Prod video). Squirted a little gas in the carb and got it so pop off and run for a few seconds. Today I had to install a few oil lines and afterward tried starting it again and it would not fire off. Strangely it also would crank with the key off and once continued to crank after I pulled the wire to the starter button. With the key on I get about 3 volts to the coil and I do get a spark to the plugs. I noticed the positive lug on the solenoid was loose in the solenoid body when I installed it. Does this sound like a bad solenoid?

 

[JMOR]

Probably, but you might try tightening the solenoid post.

 

[Tall T]

I finally got my 8N back together after engine rebuild (12v conversion, front dist.) Installed new solenoid, key switch and wiring harness (per JD Prod video). Squirted a little gas in the carb and got it so pop off and run for a few seconds. Today I had to install a few oil lines and afterward tried starting it again and it would not fire off. Strangely it also would crank with the key off and once continued to crank after I pulled the wire to the starter button. With the key on I get about 3 volts to the coil and I do get a spark to the plugs. I noticed the positive lug on the solenoid was loose in the solenoid body when I installed it. Does this sound like a bad solenoid?

When tightening the solenoid post, see that the post itself doesn't turn with the tightening so you don't sever the connection inside.
You might try grabbing the bolt before the nut with leather in vise grip jaws.

 

[Eman85]

It would crank with the key off....That's normal if the tractor is wired properly and you mean the engine will turn over when you push the starter button. Continuing to turn over without the wire connected to the starter button means the wire is punched somewhere and grounding, or the solenoid is bad. It does sound like possible human error in the 12v conversion.