My 2007 Mercury 200 hp smartcraft monitor dispays erratic temperature in 30-40 degree weather when idling. Dispay will go from 138-105- 129 degrees several times a second. Tach rpm will jump from 800 to 2000 rpm's and no changes in sound of motor. Motor malfunction alert will beap. When dealer hooks to computer no failures are shown.
I'd double check that the SmartCraft cable has a good tight fit at the console and the engine.
So many honey-dos . . . . . so little motivation
Recommend that you unplug ALL Smartcraft cable connections (at dash, AND at engine).
Leave disconnected overnight.
Reconnect the next day, and see how it does.
BTW... precisely WHICH Smartcraft instrument to you have? If unsure... a picture is a good starting point.
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 48 years (learn something new every day).
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