This article tells how I added an electric hour meter to my 1942 Farmall H after rebuilding it. I wanted to keep an accurate maintenance schedule for my rebuilt engine and the implements I use with my tractor, but the H was never available with a tach-hourmeter and a factory type hourmeter is over $250. This system can be installed for under $35 and works well.

First, I bought a waterproof hourmeter from JCWhitney that will operate on anything from 4 to 40 volts DC. Other hourmeters need more than 6 volts.

For the power wire on the hour meter, run a wire from either ammeter terminal. If your tractor is positive ground, run this wire to the (-) negative side of the meter. If your tractor is negative ground, run this wire to the (+) positive side of the meter.

Next, you need a SPDT (Single Pole, Double Throw) toggle switch. I bought mine from Parts Express. The schematic of how the switch works is on your right.

Please note, these instructions are for a MAGNETO equipped tractor. If you have a distributor, read the paragraph at the bottom of the page.

Really simple: look at the diagram on your right. One wire goes from the switch to a ground, one goes to the negative terminal on the hour meter, and the last one goes to the grounding terminal on the magneto. When you flip the switch it ungrounds the magneto and grounds the hourmeter, allowing the tractor and hourmeter to both run. Below is a picture of where I mounted the meter on my H.

I mounted the meter under the rear gas tank support so it is out of the weather a little more. It is supposed to be water proof, but I didn't want to find out the hard way. Also, down there no one can see it unless they look for it.

It would be easier to mount there if I didn't have a belt pulley in the way.

INSTRUCTIONS FOR DISTRIBUTOR EQUIPPED TRACTORS:
You don't need the toggle switch. Assuming you have a positive ground electrical system: wire the negative side of the hourmeter to the power side of your ignition switch (the wire that goes to the coil).
Negative ground systems: wire to the positive side of the hourmeter to any wire that is powered when the switch is on (tractor running).

For the power wire on the hour meter, run a wire from either ammeter terminal. If your tractor is positive ground, run this wire to the (-) negative side of the meter. If your tractor is negative ground, run this wire to the (+) positive side of the meter.

Steven Gussey
email: smgussey@yahoo.com