I am putting my 42 Farmall H back together and have a question on wiring up an hour meter. I have one that is waterproof and works on anything from 4 to 40 volts. My question is, Is there a wire somewhere that is only live when the tractor is running? I have magneto ignition and a regulator mounted on the generator. Light switch is O, D, B. If there is no wire that is only live when running, I'll have to rig up a toggle switch and remember to turn it on every time.

I want to have an hour meter with my new engine to keep an accurate maintenance schedule, and judge fuel economy and usage throughout the year.

Steven

Hey Steven where did you get the Hour meter would like to put one on the 44h and how many $ thanks ron

Got it from JCWhitney. Dunno how good it will work but it is supposed to be waterproof and work on 4 to 40 volts. Check the link to buy one. $25.99 plus shipping.

As for where I'm going to put it, I'll probably just put it somewhere where I can see it from the seat since this isn't really going to be a full restoration, I am going to use it a lot. I'm trying to be accurate and keep the mag and 6 volt system - also the original style gauges. But I'm going to try to find some bigger fenders for safety reasons, hopefully I can make them look good.

Steven

• Hour meter from JCWhitney

Steven - All of the ideas below will work, though with a couple of clarifications:

1 - Wire the Hobbs meter "-" terminal to the regulator GEN terminal. (Assumes you have a positive ground system - if your tractor is negative ground connect the Hobbs "+" terminal to the GEN terminal) The meter should run whenever the motor is running, even when the generator is not charging (3 or 4 volts appears at the GEN terminal even at low idle...)

2 - The pressure switch idea will work - though you gotta use a NORMALLY OPEN pressure switch (one that closes it's switch contacts when it senses pressure) for this to work. Note: Nearly all vehicle oil pressure switches are NORMALLY CLOSED - contacts close on loss of oil pressure. So you can't simply grab any old oil pressure switch and have this one work.

3 - Replace the stock magneto kill switch with a DPDT toggle switch. If you wire it correctly, no relay is required.

I personally prefer #3...

I like #3 too, but what is a DPDT toggle switch? If I were to wire it to the gen terminal I would need at least 4 volts to run the hour meter - I guess once I get it together and running I can always check that out with my DVOM.

Thanks
Steven

Steve -

The diagram above shows a typical DPDT switch setup. To operate your Hobbs meter wire the "+" on the Hobbs in place of the warning light in the diagram, and wire the magneto kill terminal exactly as shown.

A DPDT (double pole double throw) switch is two electrically isolated switches in a single unit and which operate in unison. Radio Shack stocks several different types of DPDT switches which will work. Make sure you get a 2-position switch - NOT a 3-position (or "center off') switch.

Hope this helps! ...Bob M

Note - if the wiring diagram doesn't display, here is the URL: http://albums.photo.epson.com/j/View?u=4001561&a=30065733&p=60405158&Sequence=0&res=high

It helps a ton! I went to your photos page on Epson and found the diagram. Thanks Bob M for your help, now I know what I am looking for this week. I'll find a DPDT switch and wire that in when I get ready to wire everything up and it should work great. Now, to find a place to hide that unoriginal hour meter - but where I can still see it...

I love this hobby!!
Thanks again!
Steven

Steven - I'm going stick Hobbs meters on my SH and SM once the weather is a bit more favorable for wrenching outside in the shed. Thinking of fabricating a bracket to hold the meter up under the hood behind the generator and orienting the meter so it faces the ground. You'll have to stoop a bit and peek up under the hood to read it, but it will be well-protected from rain, etc. and it will be unobtrusive.

install a hobbs hour meter pressure switch in the oil pressure galley,run a hot wire to the switch run a wire from the normally open terminal on the switch to the hour meter and from hour meter to ground.the hour meter will run when the engine has pressure,will quit when the engine is shut off

Hook it up on the hot side and hook the ground to the field pole on the generator. It is only grounded when the generator is charing. That should work, I think.

Just a thought. Do you have a kill switch? Replace it with a double pole, single throw switch and add a relay. When you throw the switch it will unground your mag and energize the relay to run the hour meter.