jumping tachometer needle on Merc 4 cyl

[rcarden]

Hello,

I have twin 1999 Mercruiser 4 cylinders. The starboard tachometer (Teleflex gauge) has started to act up. With the engine running fine, the tach needle starts to jump a bit, sometimes all the way to max...then it will return to normal if I thump the gauge.

Does anyone have any idea where to begin to look for the cause?

Thanks,

Robert

 

[imported_TheMan]

Re: jumping tachometer needle on Merc 4 cyl

I don't know that I've heard of twin 4 cylinder setup.. interesting.
Anyway, if "thumping" the gauge works, I would clean all the terminal connections and put some di-electric grease on them. If that fails, replacing the wiring and/or gauge.. Tach is probably grounding out somewhere..

 

[tommays]

Re: jumping tachometer needle on Merc 4 cyl

The tack goes through the 10 pin motor plug

Mine has had the need to thump and it turned out to be a bad connection at the 10 pin plug (it is NOT as sealed as it looks)

I used contact cleaner and Qtips to clean out the sockets and pins and they got pretty dirty



Tommays

 

[rcarden]

Re: jumping tachometer needle on Merc 4 cyl

Tommays & The Man,

Just a quick Thanks for your help with my tachometer. I did as you both suggested and the problem is fixed.

I appreciate ya'll taking the time to help others out on this board.

I've saved $100's using this forum.