2012 Mercury 4.3 TKS Temp gauge dropping out

[Chobes]

Hello all. Been a while since I’ve been on the Forum. Well I just picked up a 2012 204 FSX Monterey Bow rider only 200 hours
Beautiful boat.
So here’s my issue... while cruising at slow engine Rpms. Less then 3000. Everything is fine. Once I increase RPM above 3000 the temp gauge drops to 100 degree F. I’ll bring RPMs back down and temp gauge pops back up to around 165 degrees F. Any ideas? Not sure how to proceed. Boat runs great at both RPMs.
Thanks for the help!!!

 

[achris]

First check your engine has a thermostat installed. If so, have a look at all the wiring... You may have a loose connection somewhere.