[warthog]

I have twin engine Yamaha jetboat and have been experiencing tachometer problems. Currently seeing advice in troubleshooting.

Both tachs are frozen at 800RPM and do not move when power is applied regardless of wether or not the engines are started.

Any suggestions before beginning trouble shooting?

I first suspected a fuse problem but have not found any fuses to these tachs.

Thanks,

 

[JUST-IN-TIME]

so you have 12v to the tachs
they get their signal from the voltage regulator

 

[warthog]

will check the voltage regulator for signal. Not familiar with this vessel. Thought it was electronic ignition with these jet ski engines. Will check. Do you know if the three plug input is gnd/pwr from switch/input from VR?