RPM Gauge - The Hull Truth

BsTrophy · 06-25-2007, 03:02 PM

My RPM gauge just stoped working. I check out the wires and played with them but still the gauge is frozen.

Does anyone know how to fix this? Someone told me that I need to buy an enitre new gauge, do I?

Any info would be helpful.

Thanks guys!

WildeOne · 06-25-2007, 03:18 PM

What motor? If an OB, then look to the regulator/rectifier or stator. Tachometer is likely OK.

BsTrophy · 06-25-2007, 03:29 PM

I have a 2003 125 merc 2 stroke.

thanks

WildeOne · 06-25-2007, 03:46 PM

Most Merc's take the tach pulses from a regulator/rectifier (some motors have two per motor). I would check the AC voltage into the rectifier(s) to verify the stator is OK, then check the DC output of the rectifier(s). Don't disconnect any wires, or you run a good chance of making sure you have at least one failure. The Merc OEM service manuals usually have the checking procedure well organized. You may find your battery is getting run down as well. In fact, I would check the battery terminal voltage with the engine idling first. You should get > 14 VDC. Your tach is likely fine.