toggle quoted messageShow quoted text
Your hull number is very close to mine. There is a sender on the outboard side of the engine about one third of the way down on the bell housing.
It is almost directly above the flywheel ; it has a big diameter and 2 wires with push on terminals. I would start by cleaning the studs of the sender and the solderless connectors and then use Corrosion-x.
If you do not have that sender there should be a wire hanging off the side of the 12v alternator.
That is the tachometer lead if you do not have the sender above the flywheel there should be a wire attached to it.
If the alternator is the source of the RPM’s go to an auto alternator shop. If they must replace the entire unit , make sure it is an isolated ground model.
However, my first guess is the tachometer itself. I recall having that problem on a 4jh2e Yanmar years ago.
Kimberlite Amel Super Maramu #376
From: main@AmelYachtOwners.groups.io On Behalf Of Steve Bell