Got a question on something I’m curious about. I’ve got a Jubilee that has been converted to 12V, has a 12V coil and electronic ignition.

There are two resistors on the tractor. 1 is mounted right on the back of the alternator and the other is mounted on the pushrod cover right before the coil.

The tractor is running fine but I was looking at it yesterday and thought, I’m sure one resistor is needed but with the 12V coil is the 2nd one they’ve got mounted at the pushrod cover necessary?

Thanks for any input
 
(quoted from post at 09:40:02 09/13/20) Got a question on something I m curious about. I ve got a Jubilee that has been converted to 12V, has a 12V coil and electronic ignition.

There are two resistors on the tractor. 1 is mounted right on the back of the alternator and the other is mounted on the pushrod cover right before the coil.

The tractor is running fine but I was looking at it yesterday and thought, I m sure one resistor is needed but with the 12V coil is the 2nd one they ve got mounted at the pushrod cover necessary?

Thanks for any input
If it ain't broke, don't fix it until it is!" Some 12v coils need a resistor & some don't & some have such lettering on the side of coil, some are not marked.
 
The purpose of the resistor in the ignition circuit was to keep the points from burning up. Since it now has electronic ignition, there should be no need for one in the ignition circuit.

As for the one going to the alternator, are you sure it is a resistor and not a capacitor? There should be no need for a resistor in a charging circuit.
 
(quoted from post at 11:47:06 09/13/20) The purpose of the resistor in the ignition circuit was to keep the points from burning up. Since it now has electronic ignition, there should be no need for one in the ignition circuit.

As for the one going to the alternator, are you sure it is a resistor and not a capacitor? There should be no need for a resistor in a charging circuit.
I still say leave it alone! The EI and coil can't tolerate unlimited current either, so depending on coil primary resistance, the resistor may be required. The one on alternator may be in excite circuit , needed to prevent back feed when key turned off.
 

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Here are photos of what I’m talking about. Appears to me it’s a resitor on the back of the alternator. Now I have no idea if during the original transition from 6 to 12 if they left the coil 6 volt. But right now it has a 12V coil and electronic ignition
 
The resistor in the second picture is definitely in line with the coil. The one in the first picture is simply connected to two wires coming out of the (not original) wire harness. You need to trace those wires to see where they go to be able to determine if the resistor is needed or if it is even connected to aything at the other ends of the wires. If it starts and runs and keeps the battery charged I would just leave it be as the others have said.
 
On the coil there are 2 wires on the side the wire from the resistor goes to. Where does the other wire go to?
 
(quoted from post at 13:10:47 09/13/20) On the coil there are 2 wires on the side the wire from the resistor goes to. Where does the other wire go to?
ost likely the red goes to power the EI module, and that isn't correct for the Pertronix module, but if it runs fine as is I'm not the guy to tell him to change it. Most likely the 6v neg module is same as 12v pos module, so it won't matter. Yes, I know different box & number.
 
(quoted from post at 14:05:49 09/13/20)
(quoted from post at 13:10:47 09/13/20) On the coil there are 2 wires on the side the wire from the resistor goes to. Where does the other wire go to?
ost likely the red goes to power the EI module, and that isn't correct for the Pertronix module, but if it runs fine as is I'm not the guy to tell him to change it. Most likely the 6v neg module is same as 12v pos module, so it won't matter. Yes, I know different box & number.
ext to last sentence should have read, 'Most likely the 6v neg module is same as 12v NEG module, so it won't matter.'
 
Sean, you’re saying that you think that the resistor at the alternator is
just connecting those two wires? Cause that’s what I thought also just
looking at it.
 

after thinking about it and its location... I believe its put in line with the lead from the alternator to the ignition switch to simulate the bulb or diode that would have/should have been put in line. This way the alternator will correctly sense ignition and charge immediately instead of having to be reved up to charge.. So apparently the 1.5 ohm resister replaces a ge53 dash bulb????
 
(quoted from post at 09:14:35 09/14/20)
after thinking about it and its location... I believe its put in line with the lead from the alternator to the ignition switch to simulate the bulb or diode that would have/should have been put in line. This way the alternator will correctly sense ignition and charge immediately instead of having to be reved up to charge.. So apparently the 1.5 ohm resister replaces a ge53 dash bulb????
ounds ok to me
 
(quoted from post at 09:14:35 09/14/20)
after thinking about it and its location... I believe its put in line with the lead from the alternator to the ignition switch to simulate the bulb or diode that would have/should have been put in line. This way the alternator will correctly sense ignition and charge immediately instead of having to be reved up to charge.. So apparently the 1.5 ohm resister replaces a ge53 dash bulb????

But it's not connected directly to the alternator at all. If it were installed to be the load between the alternator and the ignition switch, wouldn't it have been more logical to connect the alternator side of the resistor directly to the alternator? You never know what some previous owner might have done, but adding an extra wire in the homemade harness just to go back to the alternator for a connection to a resistor that could have been connected directly to the alternator just doesn't make any sense at all. It would have been easier to put the alternator at the ignition switch end of the wire that's already going in that direction from the alternator.
 
Meant to add this to my last post:

As I said previously, the only way to know for sure is to trace those two wires connected to that resistor to see where they go.
 
(quoted from post at 12:22:16 09/14/20) Meant to add this to my last post:

As I said previously, the only way to know for sure is to trace those two wires connected to that resistor to see where they go.
ep, short of that, it is just guessing & and thinking, "what would I have done?".
 
I agree, it's working so leave it alone.

On the first picture of the alternator, it is a 3 wire Delco that you say is working properly. Therefore one side of the resistor is connected to the output side of the ignition switch and other side of resistor to #1 pin. This pin needs a start up voltage when the engine starts up. The purpose of the resistor is to prevent feed back back to the coil when switch is turned off. Without the resistor engine may continue to run when switch is turned off.

On second picture has me curious. I see resistor in line powering the coil and a red wire connected with it and a black wire connected to other side of coil. Makes me wonder if this is a 6 volt or 12 volt external resistor required coil in a 12 volt system with a 6 volt pertronix connected across the coil. Pertronix instructions show to wire 12 volt ignitor to battery side of the resistor.

Some curious questions but main thing is its working.
 
To help clear the air hopefully on the coil questions, the red wire is connected to the positive terminal on the coil. For some reason they have the coil sitting positive side towards the coil. So it’s not hooked up red (EI) to negative on the coil.
 
(quoted from post at 06:31:50 09/15/20) To help clear the air hopefully on the coil questions, the red wire is connected to the positive terminal on the coil. For some reason [b:4264689a65]they have the coil sitting positive side towards the coil.[/b:4264689a65] So it s not hooked up red (EI) to negative on the coil.

That clears it up right there.
 
" the red wire is connected to the positive terminal on the coil." That is correct

Coil mounting orientation doesn't matter as long as it's wired correctly. You have an alternator so the system should be negative ground.

On your EI module red wire should be positive input, black should be output that grounds through the coil to turn it on and off

Coil doesn't care which way it's wired, the concern is for spark plug polarity. With coil output matching battery ground the spark plug will "spit" the spark from center electrode to ground tab. Reverse the coil polarity and spark plug center electrode will "suck" the spark from the ground tab. You get more efficient spark when it "spits" from center electrode.
 
(quoted from post at 03:54:09 09/15/20)
(quoted from post at 06:31:50 09/15/20) To help clear the air hopefully on the coil questions, the red wire is connected to the positive terminal on the coil. For some reason [b:8d5b024ed4]they have the coil sitting positive side towards the coil.[/b:8d5b024ed4] So it s not hooked up red (EI) to negative on the coil.

That clears it up right there.

Forgive me, I was about half asleep when I sent that.

The positive side of the coil is facing the DISTRIBUTOR side rather than facing back towards the rear of the tractor (battery side). So the green wire leaving resistor (why they chose green idk) is carrying power to the coil which is where the red wire is also connected to the electronic ignition. It is a 12V negative ground Petronix system.
 
(quoted from post at 10:25:05 09/15/20)
(quoted from post at 03:54:09 09/15/20)
(quoted from post at 06:31:50 09/15/20) To help clear the air hopefully on the coil questions, the red wire is connected to the positive terminal on the coil. For some reason [b:243b3f0479]they have the coil sitting positive side towards the coil.[/b:243b3f0479] So it s not hooked up red (EI) to negative on the coil.

That clears it up right there.

Forgive me, I was about half asleep when I sent that.

The positive side of the coil is facing the DISTRIBUTOR side rather than facing back towards the rear of the tractor (battery side). So the green wire leaving resistor (why they chose green idk) is carrying power to the coil which is where the red wire is also connected to the electronic ignition. It is a 12V negative ground Petronix system.
What folks here keep pounding on is the location of the resistor and the feed of power to the EI red wire. (as I mentioned back on the 13th) & as I said then and again now, "it is working fine, leave it alone, as is!!! Picture is how Pertronix wanted it, whereas you have resistor between the switch and junction of red wire and coil (first dot in wire drawing). In other words, they wanted the red module wire connected to the white wire side of resistor, not the green wire side as you have it, but....again, I say leave it as is. nothing beats success!
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