'97 Tach has mind of its own....

I've got a wacky tach (original Nautique gauge; had this same issue with my '96). The tach sometimes reads correctly, and sometimes it is much higher (and sometimes will bounce around). If I whack it with my knuckle, sometimes it starts reading correctly, sometimes not. I've ignored it because I have Stargazer, but along with some other covid-19 related maintenance, I'd like the tach to work correctly. I just bought one from Nautique Parts, and wasn't paying attention to the fact that it is Faria, the increments are 200rpm,(not 100rpm), and it doesn't say Nautique. Before I just slap the new one in, I was wondering if anyone else has seen this problem, whether it is tach failure and no choice but replace it, or if there is something else? I've tried wiggling the connectors a little, but not enough to do anything. I pulled the old one out, but if there is a chance that it is just connections rather than the unit being faulty, I'd rather put the original back in.

Any idea/suggestions?

Thanks,

Gordon

Possibly bad ground. Any other goofy things going on in the dash?

On second thought 1997 had the Down Unda tach right? Maybe you just have to turn it upside down which is right side up so you can read it. 1997 was a wacky tacky no doubt.

The tach was normal on a 97. In 98 they went to a counter clockwise rotation, very odd.

I don’t know but the counter clockwise rotation only lasted in 98 as best I can remember. It made driving one for the first time pretty different to me.

Jonny Quest wrote: KENO wrote: Do you have a little adjustment on the back for selecting the input like 4,6 or 8 cylinders. Some are inside a little hole and others are easier to see. Sometimes cycling that little adjustment with a small "tweaker" and putting it back on the 8 cylinder position cleans the internal contacts and it starts working right again if they had a little corrosion on them. Emphasis on "sometimes"    I imagine you already checked cleaned the connections to the tach.     What KENO said... On my previous boat (1994 SNOB) the original Nautique tach would go wack...just like what you are describing. As KENO described above, this worked for me. When the tach would start to act up, I would open up the dash pod to where I could get a small flat screwdriver on the tach adjustment knob/pointer/thing.   I would rotate from 8-cyl to 6-cyl to 4-cyl several times...and then re-set back to the 8-cyl "detent". It seemed that "exercising" the selector thing would chase the gremlins out. JQ

Makes sense. Probably a little corrosion/oxidation with the switch contacts. Only problem is we're not allowed on our site yet due to Covid, and since it is hit and miss when it does it, may not happen with a 5 minute hose hook up. But I'll do it and see. The original tach looks so much better than the replacement.

So, I looked at my old tach so I could try switching it from 8 to 6 to 4 cylinders and then back to 8. However, I don't know which adjustment I need to do:

If one is the selector (can't really see what it is supposed o be set at and the other one is calibrate, it looks like I have to try to figure out where 8 cyl is, and then adjust it based on readings on my stargazer. Can anyone see well enough to let me know which I'm supposed to adjust?

Thanks,

Gordon

That's a great idea; too bad I wasn't thinking and already moved it around to clean up the contacts. Looks like I'll be testing it hanging out of the dash.

Mpost wrote: Any chance that if you took the two spade lugs off and removed the plastic, there would be markings underneath????

This is what the original backside should look like from a quick search for "Teleflex tac image"

Mpost wrote: Pete, That is exactly what mine looks like in my 98. I just had to move mine last week to get it working properly again.

Thanks for that!!!!

KENO wrote: You don't want to wire it like the one in Pete's picture though Gordon, since your tach and that one have the IGN and SEND terminals reversed and it probably wouldn't work too good wired wrong.

LOL!   Good point! I guess I"m lucky my labels are so hard to see, that I have to take extra time identifying each terminal. Will probably be a couple of weeks before I at least hook up a hose; I'm replacing carpet right now.