2002 optimax 225 tach

[Alakeshore]

At idle the tach on my '02 optimax will randomly fluctuate from 700 ( which I believe is about right) to 3000 with no noticeable change in actual engine speed. Also while running at wot reading around 5100rpm it will cut out like it's hitting the rev limiter. Any ideas?

 

[Texasmark]

In the engine, go to the remote cable/engine plug and pull it apart and push it back together several times in an attempt to clean the contacts. Then go to the tach and with a nut driver or suitable tool, run the nut out and in and out and in a few times on all 3 input wires. Check your battery voltage while running the engine over 1000 rpm and look for 14 or so volts if the battery is in a high state of charge to verify that your rectifier/regulator module is functioning properly. The tach output is usually the grey wire from the regulator module.

If the above don't show a smoking gun, I'd replace the tach.