Yanmar 2GM20 Tachometer

[gbendaly]

HI all;,

my RPM dial gauje suddenly stopped, with no apparent effect whatsoever on the engine whilst running ..I checked and tightened the connections at the sender and at the back of the dial gauje nothing..what next??? ..please advise

Georges

[capngeo]

Check the grounds!

[gbendaly]

there are only two wires connected to the sender and the gauje
I thought one shoud be the ground and the other the live
or am I wrong ??

[capngeo]

True-that.... I was referring to the main engine ground, the battery negative, and the main grounds on your instrument panel. Typically the grounds are wired from gauge to gauge, and there are lots of failure points.

Once done checking/cleaning the grounds, check the circuit for continuity. The sender can be checked with an analog VOM while the engine is idling.

[S/V Antares]

I believe the sender is a simple inductive pickup located on the back of the engine above the flwywheel. This sensor actually counts the flywheel teeth as they go by. I believe the 2GM has 127 teeth. You can measure the output of the sensor with a VOM (Voltmeter) on the AC setting. Just put the leads on the two outputs. If you see anything at all it is likely working. Sounds like the Tach is bad. The sensors rarely fail.

[bill good]

Faulty connection / plug before tacho. The sensor on the flywheel is easily checked with an ohm meter at the plug to the tacho as can the 12V DC. The wire diagram is in the owners handbook.

regards Bill