Tachometer

[Chip S]

The tachometer needle on my 1993 Sea Ray 200 Overnighter (150 hp Mercury outboard) is at 400 rpm when the key is off. When the engine is idling in neutral the tachometer usually is indicating ~1000 rpm. Sometimes when I start the engine the tachometer is indicating ~3000 rpm when the engine is in neutral even though I can tell by the sound of the engine that the engine is actually running at ~1000 rpm. When it is indicating ~3000 rpm in neutral I turn it off. Usually when I start the engine again it indicates ~1000 rpm. I sanded all of the contacts at the gauge so I don't think its a corrosion issue.

Any ideas what could be causing this? After 27 years is it time for a new tachometer? If so, what would be the best match to the gauges that Sea Ray used?

 

[dtfeld]

Get to the back of your tach. Should be a little dial labeled 4-6-8 or something like that. Rotate back and forth a couple time and reset at the correct # based on the # of cylinders your engines has. 6 cylinder=6 , 8 cylinder =8.

If that doesn't fix, then probably time for new tach

 

[Chip S]

I rotated the dial multiple times and could hear crunching/crackling coming from inside the tachometer. I took the boat out for a run and the tachometer is working perfectly now. There must have been corrosion inside the tachometer that needed clearing. Thanks for the help.