Cranking 6v Cub with 12v battery

[livemusic]

The 1956 Cub I bought has a 6v battery and I suspect the battery is no good because it's probably over 10 years old. Have no idea when the Cub was last started, bought it at estate sale and the owner is deceased. I just want to see if I can get the Cub started. Could I crank it with a 12v battery or is that a bad idea? I don't have a hand crank, wish I did.

EDIT: What about buying a 6v battery charger and hooking that up to crank it? And if I got it cranked, if the battery is shot, will the engine keep running? Sorry, not a mechanic!

[rockfarmer]

If your tractor has a magneto, and it is properly timed it will start and run without a battery. You will have to hand crank it, if you have a crank. Please search for proper technique on this site, if you decide to try this method. I hand cranked mine yesterday for the first time.

If a distributor, you will need a source of voltage. I am not sure about using a 12 Volt battery to start the tractor. Maybe someone else will advise you on this.

Also, you should prime the oil pump if you are going to try to start it. Good luck.

[MilGunsmith]

6 volt is usually a positive ground. A 12 volt battery can be used, but it has to be hooked directly to the starter and the ground bypassing the starter switch. You could also do the "John Deere" start and use a tow strap and pull start it.

[inairam]

I jump my 6 volters with a 12 volt by hooking to the negative to the nut on the starter stitch and positive to a bolt head holding the starter.

If you get it started and you have a distributor and coil ignition and it dies when you disconnect the jumper battery the charging system is not working. You should be able to run off the generator for a bit dead battery or not if you have it at at least 1/2 throttle.

If you have mag it will run dead battery and dead charge system or not.

Before you jump it Check the oil and prime the oil pump.

[Boss Hog]

Take the 6 volt battery out and put the 12 volt in with positive ground , it will be fine just to start it.

[ScottyD'sdad]

Take the 6 volt battery out and put the 12 volt in with positive ground , it will be fine just to start it.

I agree with Boss. Just don't run it long, or the coil will fry.

Ed

[staninlowerAL]

Take the 6 volt battery out and put the 12 volt in with positive ground , it will be fine just to start it.

I agree with Boss. Just don't run it long, or the coil will fry.

Ed

Or add an "inline" ballast resistor between the battery power source and the input to the coil or change the coil to a 12v internal resistor coil and you can run it as long as you want.

[Frozenstate]

I have fried the voltage regulator jumping my tractor with 12 volt.

[pickerandsinger]

Take the 6 volt battery out and put the 12 volt in with positive ground , it will be fine just to start it.

I agree with Boss. Just don't run it long, or the coil will fry.

Ed

[Glen]

Hi,
Below is a Cub owner's manual, made in late 1955. The experts on here recommend that people read it, it has lots of info about operation, maintenance, and lubrication. There is a table of contents on page 1.

http://farmallcub.com/rudi_cub/www.clea ... index.html

Here is info about priming the oil pump.
The oil pump can lose it's prime when the Cub sits for some time, then it might not suck up oil from the oil pan. Then there is no oil pressure when the engine is running.
Engine damage can happen running the engine without oil pressure.

Below is a picture of where the hole is that I use for priming the oil pump. Just remove the oil filter top, and oil filter, and it is easy to see, use a light if you need to.
I fill a clean oil can with motor oil, and pump it into the hole, you might need more than one filling of the oil can to fill the passages in the engine.
Put the oil filter in, and the cover on, before starting the engine.
Watch the oil gauge after starting, it takes 15 - 20 seconds for the gauge to show pressure, it has to fill the oil filter housing before the gauge will show pressure.

[livemusic]

Somebody wrote: "Take the 6 volt battery out and put the 12 volt in with positive ground."

What does "with positive ground" mean?

[Bob McCarty]

What does "with positive ground" mean?

The positive terminal on the battery is connected to the ground wire. Modern vehicles are all negative ground.

[Glen]

Hi,
A 1956 Cub was originally positive ground. The positive post on the battery is connected to ground, and the negative post is connected to the cable to the starter.
The Cubs were all positive ground from 1947 - mid 1964, when IH changed them to 12 volts. The original 12 volt Cubs are negative ground.
There is electrical system info and diagrams in the owner's manual I posted above.

[Landreo]

Using a 12 volt battery on a 6 volt system risks burning the coil, the cutout/regulator, or both. Using a 12 volt battery for a quick start then quickly disconnecting the battery before the generator has time to start charging can be done.Once the generator starts charging, the cutout will close and that 12v battery will back feed into the generator possibly welding the cutout points together. Don't just put a 12 volt battery in the tractor without addressing the 6 volt charging issues.

[pickerandsinger]

If you bought it at an estate sale with no proof of it running, and you intend to keep the tractor, you need to go thru the tractor and check it out thoroughly ...It likely is not a turn key acquisition...You just want to start it...????....You should change all the fluids etc , at least check them...Does the engine turn by hand...Lots of things to think about..Just to start it on 12V Boss and ED are IMHO good to go...You want to run it around with a 12V ...Put a resistor in line before the coil or buy a 14 dollar 12V coil with internal resistance and disconnect the charging system...It will run for days without needing to be charged.Gonna keep it original no matter what...Get a 6 volt battery ( charging system could still be bad) ....Its all in what you're trying to accomplish in the long run...Dave