Re: Yanmar tach reads low rpm
You could try adjusting the pickup ever so slightly closer to the flywheel.. could be a proximity issue, but be sure to avoid contact
Alternatively get a label maker and put "x2" on the tach readout
1984 Fast/Nicholson 345 "FastForward"
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)