Do I really need a redistor on my 12V conversion?

Hello again,

Been troubleshooting my new to me Jubilee with a 12V negative ground system. At first the can't keep running was traced to poor fuel flow from a clogged fuel filter. Starts and runs much better now, but will still die out after a longer period of pulling. Noticed that it still had the 6V coil in it so bought a new 12v coil. The new coil says to use an external resistor or resistance wiring. I found a ceramic looking resistor under the dash that was not hooked up, and I'm wondering if that needs to go in the line that feeds the coil?

Thanks for any help.

Tom
 
"use an external resistor " Sure, that label means you need a resistor. Without knowing the primary coil resistance value, the resistor value needed will be a guess.
 
Once upon a time I had 2 MF 35s, one gas and one diesel. The service manual specified 5 amperes for the max break current for the points.
Considering most points are identical in their surface contacting area, even though some have a ventilating hole in the center of one side, I'd assume
that number would be good for all ignition systems.

So, considering you are running at PTO RPM for extended periods and your battery charging device is putting out 14V then 14V/5A is your minimum
resistance.......2.8 ohms DC resistance. Doesn't matter if it's all in the primary coil wire, in an internal resistor and the coil wire or an external resistor
and the coil wire. I think I bought a tapped one at NAPA once had 2 or 3 taps so you could get what you needed for different installations.
 
(quoted from post at 15:09:09 07/30/18)
Mine measures 5.3 ohms. Too much resistance?

Tom
f it is labeled as you said, "use an external resistor ", then I would say that your 5.3 Ohm measurement is in error. That number is even too high for no resistor required!
 
(quoted from post at 20:35:05 07/30/18)
(quoted from post at 15:09:09 07/30/18)
Mine measures 5.3 ohms. Too much resistance?

Tom
f it is labeled as you said, "use an external resistor ", then I would say that your 5.3 Ohm measurement is in error. That number is even too high for no resistor required!

That is the measured resistance of my resistor on the dash.

Tom
 
(quoted from post at 16:01:46 07/30/18)
(quoted from post at 20:35:05 07/30/18)
(quoted from post at 15:09:09 07/30/18)
Mine measures 5.3 ohms. Too much resistance?

Tom
f it is labeled as you said, "use an external resistor ", then I would say that your 5.3 Ohm measurement is in error. That number is even too high for no resistor required!

That is the measured resistance of my resistor on the dash.

Tom
n that case, I suspect that such resistor was for a different purpose than a coil ballast resistor.
 
I've seen several 6 to 12 volt conversion kits come with a resistor that is way too high in value. My 8N and my brother's Jubilee both came with a conversion kit and a resistor that measured in the 5 to 6 ohm range. Should be about 1 1/2 ohms to match the 1 1/2 ohms in the 6 volt or "12 volt external resistor required" coil.

I agree with the NAPA IC14SB (or equivalent) coil and get rid of resistors.

By the way the IC14SB coil primary has one continuous winding of wire that measures about 3 ohms. It does not have a resistor in series with the coil enclosed in the can.
 
Is your alternator 1-wire or 3-wires? On the NAA/JUBILEE and up 12V conversion, as with any system 6V or 12V, having the correct components and the correct wiring is very important. Don't trust what is marked on the box, with any new part. Verify yourself. A 6V coil will read 1.5 OHMS static, measured post to pigtail. A 12V coil will measure 3.0 OHMS. With a 12V coil, no resistor is needed.

Tim Daley(MI)
 

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