automotive inductive tach/timinglight

[wormboy]

Howdy,
I am curious whether there should be a different read from an inductive automotive tachometer vs the tachometer hooked up to the engine. I am reading a significantly higher rpm on the inductive tach than the tach on the console, and I think the idle rpm on the dash tach seems closer to what the engine sounds like.
The engine is a evinrude 150Hp V6; the tach is set to 12 pole.
Thanks!!

 

[jtexas]

Re: automotive inductive tach/timinglight

car engine spark plug fires on every other rotation, so the inductive tach doubles the count...your 2-stroke plugs fire on every rotation

 

[wormboy]

Re: automotive inductive tach/timinglight

Thanks-- I had thought there might be a difference, but wasn't sure.
Appreciate the reply and the explanation!