Tachometer registering too high

Otter-BelleHavenMarina · Posted: Sun Sep 10, 2006 11:02 am Post subject: Tachometer registering too high

Seeking some advice from the great minds on this site. For the past 539 hours on my Honda 90 outboard, the tachometer readings have been entirely consistent, including last weekend. Yesterday, I went out and the tach seems to be reading about 2,000 rpms too high all of a sudden.

I've seen posts here from folks whose tach read too low - 4,000 at WOT. Anyone have the opposite happen with their engine? Engine sounds normal and performs as usual. And suggestions?

Many thanks,

digger · Posted: Sun Sep 10, 2006 11:13 am Post subject:

Often times a ground wire on the tach itself. Pull the connections at the tach and reconnect, then try it. Also, you could wiggle the wires a bit while at an rpm range and see if it changes.

Otter-BelleHavenMarina · Posted: Sun Sep 10, 2006 11:49 am Post subject:

Thanks Digger for the quick response. Will do and will let you know.

Pat Anderson

Yes, that started happening with the tach on Daydream...tach would be normal for a while, then start registering 6,000 rpm, with no change in the sound of the engine. It would stay up there, maybe come back down, maybe not. Very disconcerting. Rick from the factory said that is a sign that the tach is starting to go bad. He replaced it, sounds like that is what you might need to do too.

MikeMac · Posted: Sun Sep 10, 2006 5:37 pm Post subject: Tach

Otter,
I've occasionally had the same problem with my Honda 75, usually in the 1000-2000 RPM range which is at pretty slow speeds. It jumps up to like 2800 RPM, and I know I'm not going that fast! So far a bit of, uh, percussive maintenance has solved the problem. I thwack the tach with my middle finger on the top of the glass and it returns to what it should be reading. I feel kind of guilty about such a crude repair, but that guilt seems to pass. Oh well, we all have our personal demons. I also agree with Digger, wiggling the connections seems to help too.

Don't let it get you down!

Mike

Otter-BelleHavenMarina · Posted: Mon Sep 11, 2006 8:45 am Post subject:

Thanks guys. Jiggling wires and thwacking the dial are the kinds of recommended fixes that are within my mechanical skills! Hope to get out this week to give them a try.

Jack in Alaska · Posted: Wed Sep 27, 2006 3:21 am Post subject:

My 1997 90 hp Honda has started to do the high tach reading trick also. I discovered myself the "thump" on the glass trick but it seems like such a crude fix.
Is it a bad tach, poor ground or poor wiring??? Can anyone tell me.??
Thanks