Re: Cub Farmall will not start

Thu Sep 19, 2013 9:55 am


Here is a schematic that shows a standard 6 Volt Cub equipped with a Magneto and has the lighting package.


This is the a trouble shooting chart that may be of use to you.


David D wrote:Recently I had the tractor worked on, because the last time it was running it would run for about 10 minutes and shut off like it was starving for gas. It would start fine when the battery was charged up and it would start by hand cranking. It had sat in the barn for a year or two.

Here is a good procedure to ensure that your Cub does not experience fuel starvation issues. This is something you can do yourself for the most part.

  • Check the gas tank for rust, dirt and crud. If there is evidence of it, drain the tank filtering the fuel. Refill then drain again filtering the fuel. Continue until no more dirt/crud/rust particles are present. Rock the tractor back and forth to stir up the residues in the bottom of the tank and behind the baffles.
  • Check the fuel sediment bowl. Clean well.
  • Check the fuel line itself for blockages from built up varnish. It is highly unlikely but .... it will at least eliminate that very slight possibility.
  • Check the inlet screen in the carb to ensure that a) the screen is present, b) there is no dirt/crud/rust blocking fuel flow.
  • Check the main jet - ensure both orifices are clean .. The large orifice on the side of the jet - check for varnish .. hold the jet up to natural light and see if there is a film. The longitudinal orifice at the end of the jet - clean with a soft copper wire - ideally 1 strand of twisted pair/aka telephone wire.
  • Finally and this requires removing the carb - check the needle and cage. Sometimes dirt/crud/rust can end up in the cage and block fuel flow. More likely will be the presence of varnish. Again hold the cage up to natural light and see if there is a film obscuring clear vision.

Hopefully this will help solve the no-start issues.

Re: Cub Farmall will not start

Thu Sep 19, 2013 9:18 pm

Jim Becker wrote:Here are the 2 most common Cub wiring diagrams. They changed from the first to the second in mid-1950. You will need to determine which applies to your tractor.

I still think your problem is a drain on the system when it isn't running, as I said on Wednesday. The drain should be easy to isolate.

Looks like I failed to put the link into this post. Here it is:
Forget the fuel system. Don't waste time on the generator troubleshooting chart above. Neither of them is your problem.