6 volt positive ground

[Jack Wilson]

I'm new to the forum. I read some posts last nite about positive ground on 6 volt battery. Is all 6 volt cubs positive ground? I have three cubs, two had 12 volt batteries when I bought them and one had a 6 volt. I tried using a 6 volt in the other two and the starter hardly turns over. I trying to learn about cubs but don't know what to look for to figure out if it is 6 volt or 12 volt. For this reason I'm thinking of converting all of them to 12 volt.

[John *.?-!.* cub owner]

If they were origianlly 6 volt, they were positive ground. later ones were 12 volt negative ground. anytime a 6 volt one was changed to 12 volt they were normally (but not always) changed to negative ground. Regarding the 12 votl ones not turning over good with a 6 volt nattery, they may have a 12 volt starter, 12 volt cables (smaller and won't carry sufficient current for 6 volt starting) or may have bad connections at battery, starter, or frame ground.

[Bigdog]

Jack, all cubs prior to mid 1964 were 6 volt, positive ground from the factory. So if your cubs were older than that, they should have 6 volt electrical systems. If they turn over slowly on 6 volts, take a look at what is being used for battery cables. 6 volt systems require a heavier cable and clean, tight connections are essential for the high current flow during starting. If your battery cables have been replaced with smaller 12 volt cables they may be part of your problem. Do not forget to check the ground cable and connections as well. 1/0 welding cable makes great battery cables.

[DuxburyFarmall]

Welcome to the Forum Jack!

Chad

[Jack Wilson]

Thanks for all the information. All three cubs are older than 1950. Two have ser. number plates missing on the right front side. Is the number stamp on the engine block on the left rear the seral number? I have been connecting the 6 volt battery backwards. Will this burn anything up? Thanks again for all your help. I bought all three of these cubs in the last 30 days and probably got in over my head.

[Bigdog]

Jack, you should not have done any damage by connecting them backwards. If you change them to make them correct, you will need to do a couple of things. First of all, it is possible that somewhere in the past, the wiring to the ammeter was changed to accomodate a negative ground system. With the battery connected properly (positive ground) and the tractor not running,turn on the lights (or igniton switch if you have battery ignition) and observe the ammeter. If the ammeter deflects to the negative side under load, it is connected correctly. Then, when you know the ammeter is wired right, you need to polarize the generator before you start the tractor. This is done by momentarily touching a jumper wire from the battery or "Batt" terminal on the regulator or cutout to the "Gen" terminal on the regulator or cutout. All it takes is a momentary contact and you should see a slight spark. This will set up the residual magnetism in the generator so it will charge in the correct direction. Then when you start the tractor, run the throttle up to about half-way or better and check to see that it is charging.

Don't worry about being in over your head. Just bring any questions here to the forum and we'll try to help if we can.

[Buzzard Wing]

You sure came to the right place for the answers!

I am sure that you are on the right track now but just to let you know that converting to 12 v would require new lights (bulbs) generator, starter and regulator. Not a cheap proposition and the parts are pretty tough to come by. Lots and lots of 6 v cubs around.

['Country' Elliott]

Hey Jack...WELCOME to the Board! Most of a Cub Owner's 6 Volt electrical problems end up being traced back to POOR POSATIVE GROUND CONNECTIONS. It is essential that 6 volt Cubs have CLEAN, POSATIVE GROUNDED connections to operate correctly. The slightest bit of corrosion, or rust can result in breaking the electrical connection. This is very true on batteries...lights...and starters. Keeping the connections CLEAN will result in a 6 Volt Cub that STARTS EASILY and CHARGES CORRECTLY!

[Jeremy58Cub]

What is the proper gauge wire to use for the battery cables on a 6 volt system? I am thinking of changing the old ones out to get more juice through. I don't know when they were changed last. Perhaps never???

[Bigdog]

1/0 welding cable makes great cables. 2/0 is even better if you want to go that heavy.

[Buzzard Wing]

As a side note, they must have figured out that grounds were a problem especially for lighting that they added ground wires to the lights when they changed to 12 v.

You could also use a jumper cable as a temporary ground to help isolate the problem.

[Ron Price]

Recently I purchased a cub. It had a 12 volt battery in it with negative ground. When I tried to start it smoke came from under the hood. I couldn't tell where it came from. The owner of the cub had died and his boys put the battery in. The data plate is missing but from the other numbers I think it's a 1951. Help!!

[Ron Price]

I need advice from the forum. I am stuck on stupid. The 6 volt battery I purchased sparks when I connect it negative or positive ground. Help!!!!

[Buzzard Wing]

Likely a short to ground somewhere.
Your Cub should be 6v positive ground, but that was a long time ago. Wiring diagram in the operators manual..... a new wiring harness could be worthwhile depending on the condition.

[staninlowerAL]

Ron, welcome to the Forum. Early cubs were 6v, pos ground. Your problem is probably more directly related to bad wiring than the 12v neg ground battery installation. You are likely going to have to remove the hood/fuel tank to get a good look at what's going on. One possible cause would be stuck points in the VR which would cause the wiring to heat up when the switch is on. Pictures would possibly help ID what you have. Prime the oil pump before you try to start the engine (if you haven't done so). If you have a magneto instead of a battery ignition system that brings up a whole different approach to the problem. Don't connect any electricity to the magneto, you will likely damage it and repairs can be costly. Suggest you start an new post so you will get more exposure to your questions (I noticed that the original topic here was posted in 2006.) After your second post, you can then also access the manuals at the Quick links tab (top left corner of this page, pdf folder) after your second post. Good luck and keep posting.