farmall h

farmall h quit running last night seems to have very little spark any ideas what I need to be looking at

does the on off switch co to ground when it is off

That depends. If you have a magneto, then the switch goes to ground. If a distributor, then not.

Do you have a distributor with a 12 volt conversion and a resistor? If so most likely the resistor has gone bad. If this isn't the problem then we need more info as to what you have.

it has a magneto

it has a mag

I wish we could see through the wires and fiber of the internet to assist visually.
We need to know things to give clear answers. so I will give some universal answers. There is a spectrum of H Farmalls from 1939 through 1954.
If the tractor has a magneto ignition, the magneto looks kike a one piece device with a black domed bump on the top. This dome is part of the unit, and held down with screws in the corners of it. a single wire leads from the bump to the place where the spark plug wires come out. If it has a point and coil ignition, the ignition looks like an old wooden potato masher with the wires going to the plugs on the left when standing there. The image I have put here is shape accurate, but they could be painted red, or black.The top picture is a distributor, the bottom a mag.
If a mag, the device makes its own electricity and turns it into a high voltage spark. it is not connected in any way to tractor voltage or battery power. The wire attached to the side of it (or in very early Tractors, a push pull cable like a choke cable) is used to ground the internal electricity and shut off the engine. The wire goes to a switch on the little panel that pushes to stop, and pulls to run. This switch has only one terminal, and relies on the switch housing to be its ground. The switches can fail, but usually this causes them to keep running, when it is pushed in. Internally there are pretty complex parts. A set of gears with timing marks, and a set of electrical "points" that need to be clean and adjusted to .013" at a certain point when a small 4 lobe cam opens them.

A distributor has electricity going to it from a similar looking, but different acting switch. This switch is connected to the amp gauge. The wire from the switch goes to a coil that is mounted on or near the distributor. From the coil a short wire goes to the side terminal on the distributor. The distributor is less complex, and also has a set of points under the cap. These are to be clean and adjusted to .020" when on the little cam bump. To test the voltage, there should be at least 6 volts where the wire attaches to the coil. Testing the other side of the coil with the points closed, should find no voltage. With the points held or moved to open, there should be full 6 volts there as well (or very close).
If you include pictures, or tell us more we van help. If this information gives you the creeps, watch videos and or get a knowledgeable helper. A repair manual is also needed. Jim

it def is a mag going to check the switch im not capable to work on the mag so if that is what it is I will have to send it to someone to rebuild

I saw your reply below about your tractor having a mag and you didn't feel you could work on it. I just bought a BN with a mag and had no spark. I cleaned the points and still had no spark. I then attached a condenser on the outside of the mag where the kill switch connection is and now I had spark so no spark was due to a bad condenser. I took off the plate again covering the points and condenser and properly installed the condenser. I was working in 15 degree wind chill so I was trying to make things as simple as possible without freezing to death. People on this site can walk you through changing points and condenser if that turns out to be the problem and save you a lot of labor cost.

On a mag it could be as simple as the shut off switch of even the wire running to the switch. Easy way to figure it out is disconnect from the mag and see if it runs. If it does then the wire or switch is bad.

But it could also be as simple as the points needing to be cleaned and or replaced which is not all that hard to do either

H4 or FM mag?