L3200 Tachometer Reading Wrong Sporadically

[Hellcat Farmer]

Hello,

I am a new member here and I have an L3200 HST that I have been using without any issues around our farm for about four years now. I take excellent care of the tractor, it lives inside most of the time and its duties are primarily resurfacing our arenas and moving manure.

This morning, I was resurfacing out indoor arena when I noticed that the tachometer was reading off the charts. It was pinned down around the hour counter, but I the engine was not revving any higher than it was before the tach started acting up. Prior to the problem, I was cruising in Mid range just below the PTO mark.

When I saw the gauge acting up, I immediately stopped and brought the engine speed down and the tach needle slowly made its way back to just below 1,000, which I believe is normal idle speed. I started moving again, bringing the engine speed up to the PTO mark and it was fine for a few minutes, then it started bouncing around, then it went crazy again, with the needle pointing at the hour counter. Again, I am sure that the engine speed is not soaring when this happens, just to be clear.

So i dropped the drag and the tractor sat for a few hours before I had to use it again. When I started it up the second time, everything seemed fine for about 15 minutes, then the needle started creeping up past the PTO mark when the engine speed was consistent.

I have searched through the forums and Ive found lots of reports of tach problems, but not like this. Everyone else's seem to stop working, where mine is reading wrong, but only at times. Is this a gauge failure? A cable issue?

Thanks in advance for any light that can be shed on my issue.

 

[Dave_eng]

I suggest disconnecting the tach cable at the non gauge end.

See if the inner cable will pull out of the outer sheath.

Examine inner cable carefully for signs of pending failure.

A new cable is not expensive.

30.1 CABLE, FLEXIBLE - TC420-34653 $26.11

The Workshop Manual makes no mention of the tach at all that I can find.

Lubricating the inner cable needs to be done using a special lube and then sparingly. Risk is lube getting into tach head.

For $26, my inclination would be to replace the cable and hope it is the fix.

Any signs of spiders or insects in instrument panel?

Dave

 

[Roadworthy]

Pull the inner cable out. Clean it well and inspect it carefully. If it seems in good condition you can just try lubricating it as Dave suggested. That may clear your problem. Make sure the outer cable is not pinched anywhere or bent around a tight corner somewhere.