Hour meter "broken"

[Doc_Bob]

I have a New Holland TN70A. 70 HP 3-cyl Turbo Diesel. Power shuttle, 8X8, and runs great. A few days ago my wife came out and said it was time to get off the tractor, as we had to go to party. I looked at the hour meter and it showed I had been on for 1.1 hours, yet my wife said I was on for 2 hours

So, rather than argue with her (she is always right ) I checked the next day and she is right (duh). I ran that TN70A for 2 hours and the hour meter only showed 1.1 hours. The work was stop and go, idle to 1300 rpm, 5 and 6th gear. Moved some busted up concrete, moved some mulch, moved some dirt. I was off and on the tractor 30 times. I never turned the tractor off.

So, is my hour meter busted?
Bob

 

[rswyan]

Maybe .... but maybe not - it might just be like my Kubota B2910 which records "hours at PTO rpm" .... if you are running less than PTO rpm it may just be rolling over more slowly.

 

[mjarrels]

My ford hour meter is really broken however if it did work it would have to be at 1412 rpm's to click over... I rarely exceed 1000 rpm.

mark

 

[roxynoodle]

A lot of tractors don't record hours that are at idle. That is probably the case with yours. See what happens with it based on what you were doing. If you mow for 2 hours I would expect it to show 2 hours, but if you are doing something where you have idle time I would guess it would be less. If you see that then your meter is working.

 

[JerryG]

Most tractors (especially as the size goes toward the larger side); have hour meters that are set up to read one hour at the PTO speed of 540 RPMs. If your PTO speed is running at 270 RPMs (half PTO speed), then it would take two regular clock hours to register one tractor hour There are some tractors mainly smaller ones that have an hour meter that runs one tractor hour for one clock hours. These are usually electric and will run any time the key is on whether the engine is on or not.

 

[john_bud]

Doc,

The meter is really an RPM counter. It is calibrated to show "time" at one rpm, probably the listed PTO speed. My Kubota is calibrated for 2600 rpm, when I do loader work at 2000 rpm the clock reads slow. My Ford is calibrated for 1515 rpm, when I use the backhoe at 1800 rpm, it's hour count accumulates fast.

It is a far better way of maintaining the tractor. Wear occurs every rotation, counting the actual rotations and not the ignition switch "on time" shows reality. It does give you a double take if you are thinking of it as a clock!

jb

 

[Doc_Bob]

Thanks to everyone for the explanations. I am glad that what my hour meter is doing is "normal".
Bob

 

[Jay4200]

So, is my hour meter busted?

No, hour meters don't measure hours, but actually measure in units of hours*RPM/PTOrpm. The units are still in hours (since the RPMs cancel), hence the confusion.

To clarify, if your tractor's PTO speed is 2500 RPM, and you run your tractor at 1500 RPM for 2 hours, your hour meter will read:

(2 hours) * (1500 / 2500) = 1.2 hours

I was pretty confused by this when I first got my tractor too.

Jay

 

[Doc_Bob]

No, hour meters don't measure hours, but actually measure in units of hours*RPM/PTOrpm. The units are still in hours (since the RPMs cancel), hence the confusion.

To clarify, if your tractor's PTO speed is 2500 RPM, and you run your tractor at 1500 RPM for 2 hours, your hour meter will read:

(2 hours) * (1500 / 2500) = 1.2 hours

I was pretty confused by this when I first got my tractor too.

Jay

Thanks. I thought I was losing my mind . Are all hour meters that way?
Bob

 

[PineRidge]

Are all hour meters that way?
Bob

Short answer, no.