Tach bouncing over 7000 rpms

[ericmschultz]

Hi Guys,
I have been having an issue for a while now, where my port motor tach starts bouncing if I go over 7000 rpm. Tach is fine at slower speeds. The rpm's are not chaging, just the tach reading. I don't see any cavitation issue. The boat has 30hrs. On it. 2008 sx230... thanks for any help you can give.

 

[Scottintexas]

@ericmschultz glad to have you on board, you boat has High Output engines doesn't it?

We don't see very many tach failures, when was the last time you changed the spark plugs ? it may sound foolish but these engines are very finicky about plugs and a new set can solve a multitude of problems.

You could also switch the inputs either at the back of the tachs or at your YDS hook ups behind the circular panel in the engine compartment to see if the problem follows to the other tach.

 

[Marvin willis]

I'm guessing a gear is stripped in the tach and its trying to grab and slips. Maybe?

 

[Bruce]

This might be helpful http://greatlakesskipper.com/beede-946479-yamaha-jet-boat-tachometer-w-systems-check-gauge

They have other options if the model number does not match yours.

 

[Gym]

@ericmschultz. Have you tried swapping the tach inputs as @Scottintexas suggested? It's pretty easy. Just pull the 4 screws on the face of the instrument panel, reach in and swap the connectors between tachs. That should tell you pretty quick if the problem is the tach or elsewhere.

 

[ericmschultz]

Thank you guys for all your help! I switched the plugs on the tachs and that looked to be it, so ordered a new tachometer and that was for sure issue. So happy it was just a gauge and not the engine. Sorry it took so long to say thanks, I don't get out on the boat very often because of my kids sports. Thanks again!