Ford/NH 1715 Hour Meter

[kc5gxc]

The mechanical hour meter has stopped. Tach is in same unit and works great. It's mechanical. I pulled the unit out of the dash but cannot get it apart to check. Does anyone know how the bezel on this combo gauge comes off ? I gotta get it off to pull the unit apart. I put a few teeth marks on it trying to dissamble, but stopped before I broke it.
Thanks, Pete

[dfkrug]

I don't know the NH tach/hr meter, but I had 2 of the combo guages
go bad on my Deeres. I took apart the guages just to see what the
failure mode was and the plastic worm gears for the counter had stripped
out. I had to peel back the metal edges of the guage to get it open.
A new guage was not excessively high, as I recall: $55?

Maybe Yanmar and Shibaura use the same supplier?

[kc5gxc]

Thanks, df
$55 huh? I reckon I'll use the calendar then......ha ha.
I knew I'd break if if I kept trying to open it.
I keep a log book on it and don't put that many hours on it. Heck, I go by the calendar for my truck, as I don't have a lot of mileage.
Do you know if you are supposed to lube those plastic tubes the drive for the tach is in ? I gave mine a shot of oil when I had it open. Guess that plastic is resistant to oil or it wouldn't be on a tractor ? Or hope so!.
Thanks for the info............Pete

[dfkrug]

Pete, you can also add an electric hour meter. They are inexpensive
and you can put it in some other location. Having an hr meter is pretty
important, IMO.

As for the tach drive cable, I lube mine whenever I open up an old one.
This is usually the part that fails, so it adds to its lifespan. I use motor
oil or 3-in-1 oil.

[kc5gxc]

Thanks for the info, df.
I will think about that electric meter. I got one off a dozer, but it's 24 volts. Appreciate the help.
Pete/MS

[Dataway]

Do the electric hour meters vary accumulated hours based on RPM like many tach/hour meters do? Don't NH tach/hour meters "pro-rate" hours based on an RPM x Time ratio?
JohnnyB

[North Dakota]

The hour meters on tractors record hours at different rates based on the RPM of the engine. The hour meter should read pretty close to regular time at a certian RPM (most likely different for each size of tractor and engine type/size) Any RPM above the tractor norm will read faster then normal time anything less it will read slower. I think my Manual states that somewhere around 2000 RPM is normal tractor operating RPM.

[dqdave1]

Ithought my TC 29 hour meter worked just as a clock; every minute it runs is a minute on the hour meter.

[North Dakota]

Originally Posted by dqdave1

Ithought my TC 29 hour meter worked just as a clock; every minute it runs is a minute on the hour meter.

I checked my manual and it states "The hours and portions of hours your tractor has operated, based on an average speed of 2170 rpm. Engine speeds below 2170 rpm accumulate engine hours at a slower rate than clock hours. Engine speeds above 2170 rpm accumulate hours faster than clock hours."

I'm pretty sure this is true for all hour meters. Just the average engine speed would vary.