Tach calibration

[PARADOX]

My tachs are off a bit. (Gaffrigs) one is about 100-150 RPMS the other is 200+
Any one knows how can I callibrate them to match actual engine RPM's..
THx
P

[MOBILEMERCMAN]

Paradox,
I was waiting to see if anyone would jump in.

I checked thru old installation stuff I had and also looked at their site http://www.livorsi.com/tools.htm#Tools_T But found nothing in writing to help you.
Only basic troubleshooting and low voltage issues.

I do recall some of the older ones had a plug on the back. That I wouldn't go so far as to recommend messing with it. Sorry I can't be more helpful.

[PARADOX]

Paradox,
I was waiting to see if anyone would jump in.

I checked thru old installation stuff I had and also looked at their site http://www.livorsi.com/tools.htm#Tools_T But found nothing in writing to help you.
Only basic troubleshooting and low voltage issues.

I do recall some of the older ones had a plug on the back. That I wouldn't go so far as to recommend messing with it. Sorry I can't be more helpful.

Here's the story.
On her "maiden voyage" we had a laptop hooked up to the motors. Everything was ok,, but the tachs did not register "exactly" what the laptop. directly from the motors. I was told that there are some set screws back of the tachs but I didn't want to start messing with them, until I know what to do. IT's no big deal. I can hear the enginies when they are in sync.

[MOBILEMERCMAN]

I remember some had a plug sealing that screw. I just am not familiar enough with it to recommend it. If you were to mess with it I would make very, very fine adjustments to that screw a significant turn may ruin it.

[smittyseng]

My new gaffrig tach is also off by about 75-100 rpm's(compared to a monitering computer) but heres a unusual twist,it's only off below 3000,once you get pas 2800 its close then after 3200 it matches almost perfect,I'm not going to try to adjust it as I would expect the adjustment to be linear,Smitty

[FTMBOB]

The screw in the rear is for setting 4-6-8 cylinder operation. Sometimes those contacts get corroded and the tach will act flakey or read real high. This will not help in correcting a 100-200 rpm error. I believe 200 rpm +/- is considered an acceptable tolerance for the mfg. I've seen many that were off by that much. I'm sure the mfg could recalibrate one if really needed. The easiest thing is to just be aware of the difference in reading. It should be consistent.

Bob

[Strip Poker 388]

I would call tech at Autometer, there very helpfull.

[RumRunner]

It might need a filter on the wiring to clean up the signal.

[Mr Gadgets]

Years ago, I talked to a tach manufacture about checking the calibration. Using a signal generator, he gave me the frequencies that was required to see such and such rpm. I found a couple of tachs to not be linear. I switched to a Digital tach and have not looked back. They are accurate to +/-1rpm, if I remember correctly. Way too easy to use!! Some have the analog dial and digital read out. I could even see when I hit the rev limiter..
If you really want to know.. go digital.
Hope this helps.
Dick

[RumRunner]

Keep in mind if you decide to go digital that the human eye will catch a needle quicker than it can read a number.

So you should use gauge with a dial (or both)...

Another thing you can do if you're going to be really running your boat hard is turn your
gauges....

Turn the gauge so that the needle is straight up and down where you want it to be. This way at a glance you can tell if it's where it should be (straight up and down) too high (to the right) or too low (to the left). Yea they don't look as pretty when you do this but it makes running hard a whole lot easier, and safer.