Good morning everyone

E

Emmetts’s Dad

New member
Good morning my fellow cub owners,
I have an electrical inquiry for everyone I have a ‘51 cub with 6volt positive ground and it has a distributor, non-magneto, the tractor only starts when I switch it to negative ground this old girl still has all the original wires on it(eventually I will replace all the wires) my question is why is this possible and another question is when I take the battery terminals off the tractor dies is this an indication of anything like generator is working or not perhaps anyone know how to test if it’s working properly I don’t know much about 6v positive ground I can send anyone pictures if you’d like
 
you should not remove cables from battery while running, it can damage regulator/generator test charging with volt meter, follow the flow chart
 

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Emmetts’s Dad said:
Good morning my fellow cub owners,
I have an electrical inquiry for everyone I have a ‘51 cub with 6volt positive ground and it has a distributor, non-magneto, the tractor only starts when I switch it to negative ground this old girl still has all the original wires on it(eventually I will replace all the wires) my question is why is this possible and another question is when I take the battery terminals off the tractor dies is this an indication of anything like generator is working or not perhaps anyone know how to test if it’s working properly I don’t know much about 6v positive ground I can send anyone pictures if you’d like
Click to expand...

tst said:
you should not remove cables from battery while running, it can damage regulator/generator test charging with volt meter, follow the flow chart
Click to expand...
Thank you for the flow chart i appreciate it very much How does that explain why the tractor only starts with negative ground
 
that chart is for checking your charging system, starting only hooked to negative ground does not make sense to me, ignition should not care either way, it came positive ground from the factory, so make sure the coil is hooked up correctly, positive side to distributor, does the negative side have power to it when switch is on ? points set to .020 ? are the points in good condition ? not burned ?
 
it may be your ground. not sure why i think it but is sounds like a conmection is weak. i would try cleaning everything and move the.positive ground to the bolts for the battery box or the gear shift and see if the postive ground works. also make sure awg 2 cables for both.
 
tst said:
that chart is for checking your charging system, starting only hooked to negative ground does not make sense to me, ignition should not care either way, it came positive ground from the factory, so make sure the coil is hooked up correctly, positive side to distributor, does the negative side have power to it when switch is on ? points set to .020 ? are the points in good
Click to expand...

tst said:
that chart is for checking your charging system, starting only hooked to negative ground does not make sense to me, ignition should not care either way, it came positive ground from the factory, so make sure the coil is hooked up correctly, positive side to distributor, does the negative side have power to it when switch is on ? points set to .020 ? are the points in good condition ? not burned ?
Click to expand...
I’ll take pictures of it all tomorrow when it isn’t raining and much more light
 
Emmetts’s Dad said:
another question is when I take the battery terminals off the tractor dies is this an indication of anything like generator is working or not perhaps anyone know how to test if it’s working properly
Click to expand...
Hi,
The ammeter should show if the generator is charging when the engine is running.
You didn't say if you looked at the ammeter, or what it shows.
The engine should run with the battery connected positive, or negative ground.
The voltage regulators are made for either positive, or negative ground. So it may not charge if the cables are connected to negative ground, if it is a positive ground voltage regulator.
There are usually 2 sets of points in the voltage regulator, sometimes they get burned from use, and the system won't charge. If after using the flow chart it shows the voltage regulator is the problem, you can remove the cover from it, and file the points. Wipe off all filings with a clean rag, especially between the points.
Sometimes they work after filing the points. and sometimes they don't work.
Disconnect the battery ground cable before working on the voltage regulator to avoid shorting the system.
The system may need polarizing. Below is a page from the 1955 Cub operator's manual, telling how to polarize the system. You need to get it to run with positive ground first.

You need a number 12 or 14 piece of electrical wire, about 6" long to polarize it.
It can be polarized at 2 posts of the voltage regulator. The posts of the regulator are usually stamped saying what they are, between the regulator body, and the screw holes for the wires.
The A and Gen posts are the same. :)
 
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