Tach works Hour gauge doesn't

[coolnick73]

I recently went up to Camp Ripley, MN to recover a M105 I won on GL and I was going to figure out my gas(fuel) mileage (7 to 9 MPG) and the fuel consumption per hour. At my first fuel stop I noticed that the hour gauge hadn't moved even though the tach works fine.

Any suggestions on how to fix this, or will I have to replace the tach gauge?

 

[Speddmon]

from looking in the TM it appears that both the tachometer/hourmeter and the speedometer/odometer are fully mechanical. I have the same problem with my speedo. The odometer works fine but the speedometer doesn't move.

I'd say replace the tach gauge if you really want it to work.

 

[2Deuces wild]

Speedo cable maybe bad?

 

[Jake0147]

The hours on the tach are nit "hours", they are a mechanically driven method to count the cable revolutions for maintenance purposes, just lie an odometer. They don't keep correct time for hourly fuel usage unless you want to set the hand throttle to the exact RPM that keeps good time, and control your speed with the clutch all day.
But, being mechanical and driven from the same cable that drives the needle, I'd have to pinpoint the failure as being inside of the tachometer it's self.

 

[GoHot229]

Try unhooking it in the back of the guage, it'll unscrew the retaining ring then you can pull the inner cable to see if its sheared somewhere between here and there. Mine did work, then when addressing connections to some of the guages and re-assembeling it, nothing. I massed with it again fiddelind with putting it back on (cable) and it has worked just fine since. Guages for that are, like $45.00 or so new from a bunch of suppliers. Try Saturn surplus on a MV parts search.