Tach still not working correctly

[caritobito]

Hello. 2001 Yamaha 90z. My tach was acting erratic where it would sometimes work sometimes not. Start, stop, etc etc. Might even work a few hours then act up.

Soo I replaced it today with a new one. Appears to be doing the same thing when it comes on. The paperwork says that when you turn on the key the needle should zero out. Well that never happens and it is set to 6p on the back. However if I start the engine, it will sometimes kick in but If I give it some gas, it quits working again.

My battery is showing about 13.3-13.45 volts with engine running and the voltage guage shows this as well.

Can someone tell me what else to check?? I have checked all the ground wires in the console. Everything is tight and everything else works fine. Just the tach. Could it be something on the eingine that I need to replace. Read something about a rectifier?

Thanks!

[99yam40]

I believe the 90 is a 12 pole
and sounds like you have a bad/intermittent power connection to tach

[robert graham]

Tachometer on my 90C Yamaha was doing the same thing, and after jiggling around in the wiring, found it was a bit of corrosion on the in-line fuse to the tachometer. Clean, polish and a touch of grease on contacts may hopefully solve your problem.

[caritobito]

Thanks. NOt sure about the 12 pole. Its a teleflex tach and the paperwork that came with it said the Yamaha 90 6P. Didnt have a letter reference after the motor like mine's a z.

I can double check the wires again. The power connection to the tach and the inline fuse, is that on the motor? Looking at the diagram it looked like it came from the throttle area.

I may have to double check the wire and trace it back I guess. I beleive the wires on the tach were blue for the light, black, and then looked like either brown or reddish for the signal. Kinda hard to tell.

[robert graham]

Just follow each wire from the tachometer and it should come to a fuse somewhere. Also, that little slot head screw on the back of the tachometer, well switch it from one setting to another back and forth several times, then try it in each position for correct reading. It's sorta like the old tuner contacts in a radio, they get dirty and moving them back and for can sorta "clean" them off a bit, so they stay. I'm still betting on a loose wire contact or bad fuse contact. When you find that fuse look at it real close for a broken wire inside?

[caritobito]

Thanks Robert, I'll look into that hopefully tomorrow.