I would like to see if there is any advise on Yanmar
tachos that would now be 20yrs old. Mine seem to been under reading (by 22%) & has always seemed that way since obtaining the boat
. Both read the same. The face plate indicates nippon seiki n-2 pulse =97. I asked the Yanmar
agent here & they say no known problems. I have checked the readings by optical tacho & frequency generator
. The signal from the flywheel senser is good & clean. Any one had like problems?