I have an odd problem with one of the 575SCI's in my Cigarette. Could anyone advise me where to begin looking for the problem?

When the motor is stone cold (sitting at least overnight) and I start it up it runs 100% fine, but the tachometer will only register about 300 rpm. If I try to rev the motor slightly, the motor will rev, but the tach will only move slightly higher, maybe to 400 rpm. Once the motor reaches operating temp, the tach works fine all day.
I have tried tapping the tach to see if it is sticking, it doesn't appear to be. The wires are snug on it too. I also tried restarting motor.
Not sure where to look?????
Any ideas?

Not to hijack another's thread but I have a similar, but exact opposite, problem. On cold (sitting overnight) start-up the tach reads about double the correct RPM for the first 2-3 minutes then, instantly, returns to normal operation. The Tach indicates that the motor idles at nearly 2000 and a blip of the throttle will send it up to 5000+. Maybe moisture in the electronics or wiring?? All else is normal. Engine is a 1998 454 Mag MPI.

shoot some contact cleaner into the tach near the selector switch.

Then twist the selector switch back and forth a zillion times. This usually fixes it. If you cant spray near the selector, drill a small hole in the case so you can get the spray tip into it.

I don't recall seeing that switch on the tach. But I could be wrong. I also plan to check wires on tach, but I doubt that is the problem as I had the gauges out about 40 days ago.

BILLR,

What brand of gauges are yours??

Gaffrig (Livorsi)