erratic tachometer readings

[Edge180]

My tach works most of the time, but some times it's erratic and other times I watch it go beyond the capable guage (like past 7,000 rpms) all while the engine remains normal.

I'm assuming this is a grounding issue but don't know where to start. Any help is greatly appreciated.

 

[JoLin]

Re: erratic tachometer readings

At the rear of the tachometer is a small screw (the pole selector switch) that's pointed at a specific number, like 2, 4, 6, etc. A little corrosion there can produce the symptoms you describe. It's happened to several folks including me.

Take note of the number it's pointing to, then with a small screwdriver move the switch back and forth a few times. Set it back to where it was originally and try it out.

 

[pole position]

Re: erratic tachometer readings

JoLin is correct.My Carver does the same thing,one side or the other and this works.It happens about once a season to me.

 

[MH Hawker]

Re: erratic tachometer readings

Yea mine is doing that right now in fact and thats on the work list.

 

[Edge180]

Re: erratic tachometer readings

Excellent. Thanks fellas.