Tachometer not working, a little help

[tarnold5568]

I have a 97 200merc efi. When the motor is running the tach will be reading and then it will just quit. Then it will come back on and quit again. There is no difference in the performance of the motor. Can anyone give me some info on this?

[Barry]

Look at the back of the tachometer and see if there is a "settings" adjustment. Be sure to note what its currently set at then move it using a small screwdriver. This will "clean" the contacts. See if that helps you out...

[coombro]

Check wiring for loose connection from motor to back of tach.

[roughscott]

MINE DID THE SAME THING , THEN ONE OF THE POWER PACKS WENT OUT ? REPLACED PACK AND TACH WORKS FINE ?

[HURRICANEBOB]

Had a 75hp, 95 model Merc do the same. And as an added bonus, sometimes instead of dropping to zero, it would float in hgh rpm range or peg out.

Do check the easiest things first, like other posts have said, and wiring.
Do consider checking stator, powerpack, rectifiers, regulators. Anything that is in the current path to the plugs can be causing it. In my case over 14 years, I had a stator go bad and take out a tach, replaced both, only to 2 years latter have a rectifier go and take out the second tach. And it can be just the tach itself doing it.

Funny question, but did you change plugs and put in a different type? If plugs have more or less resistance than before, or if a plug wire is arching, you may have false signals or no signal running to the tach.

Not always easy to pinpoint, so again, easiest cheapest things first.

[Embrey]

monitor your charging circuit. mine was acting up too, then it started charging through the roof. replced the regulators, then everything is back to normal

[trickworm]

Voltage regulators. Pull them off and see if the back looks burned.