Tach erratic...

[Carlos Hathcock III]

I have a 1995 Merc 125 on a 170TF and on the river last weekend I noticed that my tach was reading incorrect. The needle was not fluctuating alot, it was reading wrong, only part of the time though. Was at close to idle and showing 3000RPM on the tach. It can happen at any time, but that was the one that really got my attention!!! Any ideas? Motor seems to run ok, rough when at partial throttle is all. Thanks for the help!!!

 

[Bill P]

Mine does the same thing, look back for my post, and you'll see the responses I got, maybe they'll help.