641 6 volt coil question

[ole fred]

Your resistor #105710 is the .6 ohm pictured in post #37. Guessing it does increase resistance with heat, but just isn't in the listing.
Glad its working!

As for it working, I can't say for how long. All I've done is start it to see if the circuits were correct. It would start and run fine on a full 12 volts though. How long? I doubt very long without burning the points. Right now, it is sitting in the barn with the hood off and I'm waiting for a little cooler and less humid weather to get back to it.

I don't have an ohm meter that is accurate at these low levels, so that limits my answers - and questions.
I do have a good Neihoff tester that was used back when they set up regulators - years ago. I'll put the voltmeter on the coil and seen what the voltage is there while running and stopped etc. I'll compare that with the same results on the 961 & 851 as they were both converted to 12 volts before I got them. I'm pretty sure the 961 was with the kit from YT.

 

[soaked]

Does your Neihoff tester measure amps?
If yes, with amps and volts, you can derive the ohms, as you prolly know. (Maybe that's what you're saying?)
If 12.6 v ÷ 4.2 amps = 3.0 ohms.
Would want meter to go up to 10 amps or so, as 12.6v ÷ only1.5 ohms = 8.4 amps.

 

[Duner Wi]

Your resistor #105710 is the .6 ohm pictured in post #37. Guessing it does increase resistance with heat, but just isn't in the listing.
Glad its working!

This works best if you have your engine ready to run immediately when you turn switch/ key on . Don't get on tractor, turn key on, push clutch down ,find neutral, pull choke, set throttle and now push starter switch. Key on after engine stats to rotate. This helps when it is really cold out. This is for 6 volt Ns with factory resistor.