Originally Posted by silverback
THEY ( you know the ones) had all assured me that tacho was driven by pulses from alternator! Now am one of the know alls, at least with this tacho. A wee dab of dielectric grease and good to go����
Alt is one (common) way of doing it but NOT THE ONLY ONE.
I think I found that in the Yanmar Service Manual.
Downloadable Copy posted/available in the TF Library Manual section