NAA coil polarity

What s the effects on starting & running an engine with 6v positive ground with the supply voltage to the coil running to the + side on the 6v coil?

Was there risk to the coil?

Just discovered this wiring on my new Jubilee.

Understand the power supply to the coil should go to the - side.

Thanx !

It will work either way, no damage to the coil.
Theory says it will be more efficient wired the correct way.
I would hook it up right and run it. No need to replace a good part.

As Royse says, it won't damage anything, it's just that spark plugs are designed for the electrons to jump in one direction more efficiently than the other, but it should work fine either way. If anything else in the electrical system is weak, it might not start as easy or run as well while it's hooked up with the coil orientation backward to the system ground, but otherwise it's not going to hurt anything.

So....other question then:

Most often, I have to crank & crank the engine with hopes it starts. With proper 12 volt jump starting, it fires up in a second....every time! At 6v, it cranks at a normal 6v speed. 0-gauge cables & good connections.

The supply voltage on a 6 volt positive grounded system should have the battery wire(-) to the negative (-)post of the coil and the positive post (+) of the coil to the distributor. If I understand your post correctly, you are backwards from the way I would hook it. No coil damage has accrued, but it just might start better
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(quoted from post at 00:36:03 11/25/13) So....other question then:

Most often, I have to crank & crank the engine with hopes it starts. With proper 12 volt jump starting, it fires up in a second....every time! At 6v, it cranks at a normal 6v speed. 0-gauge cables & good connections.

Click to expand...

Not much of a question in there... more like a statement.

I suppose you're trying to ask whether reversing the coil connections might make it start faster when cranking on 6 volts, and the answer to that would be "probably". If you've already switched them and it's still slow to start on 6 volts and you know for sure that all of your connections are good and clean, then maybe the starter is beginning to go bad, which could draw down the voltage at the coil while it's cranking, or maybe the battery is getting weak. When you're jumping the starter from a 12 volt battery the only thing the 6 volt battery needs to do is provide the voltage for the coil, but when you're starting it from the 6 volt battery, it has to turn the starter and provide the voltage to the coil, so either the battery is weak or something is drawing down the voltage.

An easy test to see if the spark is the problem when trying to start it on 6 volts would be to pull a spark plug wire and hold it near a good ground when you're cranking the starter with the 6 volt battery. You should see a bright blue/white spark that should jump at least a 1/4 inch gap to ground. You can repeat the same test while you're jumping the starter with the 12 volt battery to see how much of a difference it makes in the quality of the spark.

ditto what royse said.

on an o-scope it works better correct polarity.. but should work either way.

i'd check spark first. if spark is good..and it runs good once started.. check compression.

Sean -

What you are saying makes a lot of sense. I have some more
investigation to do.

Thanx !

Pete

So....other question then:

Most often, I have to crank & crank the engine with hopes it starts. With proper 12 volt jump starting, it fires up in a second....every time! At 6v, it cranks at a normal 6v speed. 0-gauge cables & good connections.

(quoted from post at 22:54:25 11/25/13) So....other question then:

Most often, I have to crank & crank the engine with hopes it starts. With proper 12 volt jump starting, it fires up in a second....every time! At 6v, it cranks at a normal 6v speed. 0-gauge cables & good connections.

Click to expand...

here is NO question there!!!!! Just like before!

Have you done a compression test?
What are the results?

Stating your symptoms over and over doesn't help you figure out what the cause is. You need to do some actual troubleshooting. If you don't want to at least check your spark by pulling a plug wire, then measure the voltage on the battery in the tractor when it's shut off, and then again while it's cranking the starter. That'll tell you if the voltage is being drawn down too much. For good measure, while you have the meter out, check the voltage on the battery After it's running to make sure that it's charging good.