Sticky Tachometer

[dedrekon]

My Taylorcraft just went through annual with no problems, but the tach has started sticking at full throttle. This happened once before years ago and I had it rebuilt.

The more often and longer that it runs, the less it sticks. Soooooooo, is this definitely a problem with the tach (or cable), or is it possibly a crud buildup situation. Is there a good (simple) way to clean up the tach and cable to see if this is the issue? I'm guessing WD40 is not the solution.....maybe Marvel Mystery Oil?

Vincent

[Guest]

Re: Sticky Tachometer

Hi Vince,

I had that problem too. I sprayed wd40 then alcohol in it. Helped for a while but eventually I bought a new one from Century Instrument. Dave

[Ragwing nut]

Re: Sticky Tachometer

What model tach?

Mike

[Vasey fan]

Re: Sticky Tachometer

In my experience, a bad cable will eventually kill the tach. We used to pull the cable out of the shroud, clean it and coat with Lubriplate when they would start to act up. It's just a band-aid fix and you usually end up putting in a new one shortly.

FWIW, WD-40 has no lasting lubrication qualities. It was originally developed to displace water, but actually reverts after a while & absorbs moisture. It does work great for getting gum out of kids hair or removing paint from your leather jacket though.

[VictorBravo]

Re: Sticky Tachometer

I had a Taylorcrft with a tach cable that jumped back and forth a few hundred RPM. The cable and housing had worn so that the square "swaged" end of the cable had un-seated from the tachometer.... due to wear the cable had become too short. A new tach cable solved the problem.

If it sticks, however, that might be another type of problem. My first suspect would be crud and dirt buildup inside the housing.

You can take off both ends of the cable and try to spin the cable with your fingers. There shouldn't be a whole lot of resistance if the cable housing is held straight.

IF this is the problem, I would use a whole can of carburetor cleaner to pressurize and blast the crud out, form the instrument side and disconnected from the engine. Then I'd use a grease gun to pump the housing full of grease until is oozes out the engine side, then install the cable.