OMC system check false alarms

"My System check (tach&#41

"My System check (tach) intermediately, and randomly seems to go through its reset sequence while running; one beep, and all LEDs on, then each LED shuts off. This seems to happen about one or two times a trip, but the last trip, it started doing it continuously, about once every 5 seconds. At the time I was in fog and in the inlet, so I continued to run. After about 15 minutes, (seemed like 4 hours) it just stopped doing it. I didn't shut the motor off until I got the boat on the trailer. The motor ran fine the entire trip at all speeds. When I flushed the motor back at the house it ran fine, and did not reset at all.
My gauge pack was purchased about 2000, and my motor is a 1986 175 EVN. It is connected with an adapter cable, and the system has always indicated faults correctly, when tested.
While running (at home), I tried to wiggle the wires on the back side of the gauge, at the motor,and between the adapter cable connectors, to see if I could make it happen. It did not repeat. All connectors are clean and dry."

"i would say,..loose conn'

"i would say,..loose conn's,...or loose pin in conn,for pwr to tach.
here's some pin ID info---> http://www.whalercentral.com/articles.php?article_id=72
Unplug at tach,fill w/di-elect grease---reinstall."

"Talked to someone who works a

"Talked to someone who works at the local marina and he told me it's a somewhat common issue with the tach, he's going to lend me one to swap out. Sounds like a good place to start. As for the power supply, I'm not seeing any fluctuation on the voltage meter when it goes thru reset. I would think it would bounce a little if the pinn in the connection was loose/intermitant."