MF 255 tachometer issue

[rslee]

My MF 255 tachometer maxes out when I crank it. It doesn’t move after that, stays pegged out. I can’t spin the tachometer cable stem at the engine when unplugged at the gauge like when the insert on the cam shaft is wallowed out. When the gauge is disconnected, I can turn the center where the stem inserts into the gauge to put it back to zero. I replaced the tach cable just in case, but the old one wasn’t too damaged. Any idea what is causing this issue?

 

[rslee]

Nobody has any experience with a cable spun tachometer pegging out? I’d appreciate any thoughts on how this might happen.

 

[number two]

Since the cable is OK,the problem is the gauge head.
It's just like an older speedometer.
Speedometer repair shops used be easy to find.
Not what's out there now.
I recall taking the tachometer on my 1978 GMC Astro to a shop in Lansing and watched the thing fall apart in his hands.
He fixed what was broken,then spun it up on his machine and added/subtracted magnetism to calibrate it.
Hope this helps .
Good Luck!

 

[rslee]

Thank you for your response. I plan to pull the tach gauge tomorrow to see if I can maybe find something to free up. It’s like the needle is stuck in position to the spinning portion that interfaces with the cable tip. It probably will need to be replaced, but I might as well try something.

 

[jkk04]

My MF 255 tachometer maxes out when I crank it. It doesn’t move after that, stays pegged out. I can’t spin the tachometer cable stem at the engine when unplugged at the gauge like when the insert on the cam shaft is wallowed out. When the gauge is disconnected, I can turn the center where the stem inserts into the gauge to put it back to zero. I replaced the tach cable just in case, but the old one wasn’t too damaged. Any idea what is causing this issue?

I had the exact same problem with the MF 30 industrial tractor.

Went through the Agco website which has most Massey Fergusson tractor parts info available (apb.agcocorp.com) to find a tachometer part number then bought and installed it about 4 years ago.


Ever since, the tachometer works as it should be.

Jkk