Erratic tach readings

[redoakwood]

I have a 88 Larson 21' Sportcruiser w/ 4.3 omc cobra purchased last year. Tach started reading up to 1000 RPM fast. Sometimes reads true, sometimes fast. Is this a ground problem or do I need to replace tach?

 

[robert graham]

Re: Erratic tach readings

I'd check/clean/tighten all wires and connections, then if that doesn't fix it get a new tach. It's probably just a loose or corroded connection, so much moisture/humidity/vibration in a boat.

 

[bnicov]

Re: Erratic tach readings

Tap on the lens of the tach when it is reading inaccurately. If it drops or goes up then chances are it is toast. Check the manufacturers website to see if you have a lifetime warranty on your tach. I had the same sort of issue and Faria sent me a new one for $40.

 

[redoakwood]

Re: Erratic tach readings

Thanks for the tip, bnicov. I have tapped and sometimes it returns to a reasonable rpm and sometimes not. I will check all grounds and get info on tach maker for probable replacement. With all the lousy weather we have been having on Lake Erie, I might as well sit at the dock and play with the boat.