2001 JD790 Tachometer Jumping

[pretendfarmer]

This just started happening the very last time I used it for the season. Any ideas on what could be causing this? The tractor only has 500 hours.

 

[seville009]

On my skidsteer, it was an indication (in hindsight) that my alternator was going bad. Eventually the tach just stayed at zero. Happened twice - first time six years after i bought it (new), and a second time almost exactly six years later (just put a new one in last week).

A simple quick check is start the engine and see if your battery voltage is up (charging)

 

[loggin]

This just started happening the very last time I used it for the season. Any ideas on what could be causing this? The tractor only has 500 hours.

I believe the JD 790 has a cable activated tachometer. Might be that you have to replace the cable..??

 

[5030]

Or lube the cable.

 

[Roadworthy]

If you have a mechanical cable try lubricating it - graphite works well. Make sure both ends are secure. If the knurled nuts start to back off the cable may no longer be fully seated.

 

[5030]

So does chassis grease actually. At 500 hours, cable replacement seems unnecessary.