Vibration tach question

[dodge trucker]

I have a couple of those "Treysit" vibration tachs. The ones that you set on an.engine and rotate the 2 halves against each other and watch the wire, to determine rpm.
Is the reading direct on a 2 cycle engine like for a 4 cycle engine? I used it on a 2 cycle Tecumseh today. It showed I was at 4500 rpm at the moment I had it on there, now cut it back til the vibration tach said 3500. It didn't sound that fast at 4500 like the vibra tach was saying.

 

[chieffan]

Never heard of such a critter. Used the dial type that was held to the end of a shaft. Or the newer electronic that give direct reading from the rotating object with a piece of chrome tape on it, etc.

 

[Propane1]

I have those rpm tachs. I’ve never tried it on a two cycle. But from what I remember they will measure any motor. Electric too. If you have the pamphlet that came with it, that may put some light on it.

Noel

 

[dodge trucker]

Don't have that anymore

 

[CRF6179]

I had to go find mine. The instructions were with it. The instructions are kinda vague, and don't differentiate between 2 or 4 cycle. It just says that it reads the crankshaft rpm. I wrote a note on mine to read it at the widest point of vibration. good thing cause I had not used it in a long time and had forgotten.