Originally Posted by PaulM
Thanks Never Monday. I agree, DON'T mess with the no load max RPM
. The Yanmar
tach may count teeth and be very robust, but mine was off never the less.
I used to install electronic ignition systems on the big industrial gas engines.
We would either utilize the flywheel ring gear
, or drill 360 holes in the face of the fly wheel
to break the magnetic pickup's field for signaling purposes.
Basically the gear
teeth (or holes) break the magnetic field and pulses a signal.
We sometimes experienced that the engines would begin misfiring or their governors swing due to a tooth being worn or broken, or the magnetic pickups being dirty or covered with metallic dust.
Missed or weak mag pulses will certainly affect a pulse driven tach. Next time if you have tach problems see if the mag pickup is dirty.