My Starboard Tach is working but jumps all over the place. Not continuously , but every 10 - 15 seconds or so picks a new RPM. Usually, 1000 RPM above the Port Tach. According to an independent tach the motors are running at the same RPM with the Throttles in the same position.

I cleaned the contacts on the back of the Tach which didn't fix the problem. I plan to swap them to make sure the problem is the tach and not something else. The Tach looks new so I am thinking that a rebuild would be the cheapest way out.

If anyone has a contrary view, or advise I would like to hear it.

Is it a Gaffrig precision or Gaffrig Performance Gauge?

Then we can send you to the right place for repair

I don't know the difference. Its whatever came on a 1999 Formula 382

1 is made by Livorsi, the other is made by Gaffrig

one line under the name or 3 lines ?

what about just replacing the glass on the front of orig gaffrigs circa 97-98

Formula uses gaffrig performance aka Livorsi

I spent 1/2 of my season trying to figure this out with my twin engine gaffrig/livorsi gages. I even changed gages. Still NFG. New ground wires, new hots, new signal wires the works. Ended up this past weekend I finally had it fixed once and for all, what a relief!

Oh yea, it was the plug wires. What I thought were the cream of the crop for plug wires are kaka. Taylor spiral pros. Put on some cheapo automotive wires and whala, rock steady tach readings all day long.

What about on line under gaffrig?

You can send the tach back to Livorsi for bench testing. They are top notch and have checked/reset several of my guages. The person you want to talk to is Ed Mannion.

I believe there was a grounding issue with tachs on some of the earlier 382s. It was solved by running a ground directly to the distributor. Search the Formula section for old threads on this topic and post this in the Formula section. Maybe MagicFloat can chime in ...?

Be sure to check your main harness plug-in at the engine. Mine was a little corroded and caused the exact same problem. A good cleaning and a little di-electric grease solved the problem.

BTW, my Gaffrig (Livorsi) guages were sent in to be reset after engine overhauls, not because of failure. Also ... Livorsi can "repair" any original Gaffrig-labelled guages, but cannot sell new ones by court order.