Tachometer

[Rinker85]

My Tach is not working. I have 12 volts from ground to the ignition hook up on tach. I momentarlly grounded the signal wire on the tach and the engine stumbled. From what I read that means the tach is shot. Is there any other test that I am missing? I also just replaced the coil. I got the coil from an auto parts store though. They matched it up to the old one. Does that have anything to do with the problem?

 

[JustJason]

Re: Tachometer

Bad tach's happen all the time. The way I test for a bad tach is to hook up my known good shop tach in it's place. If my shop tach works and the boat tach doesn't then you replace it.

 

[Rinker85]

Re: Tachometer

Ok , I dont have a shop tach though. The test that I did by grounding the signal wire and the the motor then stumbling, is that pretty much it? Do I even bother taking it apart or just replace it? Its a 1985 made by Medallion.

 

[Don S]

Re: Tachometer

I momentarlly grounded the signal wire on the tach and the engine stumbled. From what I read that means the tach is shot.

No, that just means the tach is not shorted to ground. If you short that wire to ground the engine should not only stumble, but die. If you hold the wire on the ground.

Not sure how they matched up your coils, most all look alike, just the insides are different, but either way, they type coil is not your problem.

If you have power to the purple wire, and ground on the black wire, and you know the signal wire (Gray) is working because you can kill the engine when grounding it.
You have a bad tach. Replace it.

 

[telstar1]

Re: Tachometer

I think I have a similar prob. Just purch a 2002 Trophy with next to no hours and tach reads fine about half the time the rest of the time it is goofy, always high, (from 200 1000 rpms hi).Of course it is electronic ign. which is not real familiar to me. I have a tach off a 470(non electr. ign)., did the convert to 8 cyl.on back of tach, but it just goes right off the dial.Over many years with other older non elec. ign. I would periodically have a wonky tach, Id not deal with it and after awhile after some misc engine work it would be fine again ie probably inadvertantly fixed a bad connection at coil etc. With electronic ign. Im lost ,have tried cleaning all relevant (to me) contacts still wonky.Ideas anyone?Is it so that a non electronic pre 1990 tach will not work on a 2002 electronic ign. setup or am I doing something wrong?Ideas appreciated.Thiis is a tach with other gauges built into it Im scared to even look up the price.
Telstar1

 

[PitchFork]

Re: Tachometer

I have had problems with my tach in the past what fixed it was turning the dial on the back off it that sets it up for the # of cyclinders. I turned the dial back and forth a couples of times to clear any corrision and has worked fine since. Worth a try. Its free.

 

[telstar1]

Re: Tachometer

Hey pitchfork I tried this and it worked twiddled the 4 6 8 thingy on back of tach and all is now well in tachland
Thanks
telstar1