Merc V6 Voltage Regulators

[MaggieRose]

I've noticed my RPM indicator shows intermittently higher than what the engine is actually running at (verified by sound and with a synchroscope).

I believe the signal for engine speed is sent from one of the two voltage regulators on the engine and both regulators appear to be identical, except the one not used for engine speed has the wire capped. Are the voltage regulators interchangeable, so I can try and determine if I have a faulty voltage regulator?

Thank you.

 

[Faztbullet]

Re: Merc V6 Voltage Regulators

Swap the grey wire from 1st regulator to 2nd regulator. Recheck to see if tach is still off. If still off tach may be bad. Call a merc dealer and see if he has a tach tester and have checked.