temp fluctuation

[truckboss]

Hi Guys,Got a 2000 carrera 350 mag bravo.The boat warms up normal and under power runs about 160ish.Pull back the throttle and the temp drops down to the bottom of the gauge.After a while it will creep back up to bout 160.I tried a new thermostat and same thing,last year replaced the impeller and every thing was fine but first time out this year problems.thanks in advance

 

[tpenfield]

:welcome:

Usually you would see the opposite effect that the temperature would spike up after throttling down. Anything happen with the gauge as far as wiring, etc?

Open or closed cooling?

I would check the thermostat housing and all of the hoses to see if they are clear.

 

[alldodge]

Howdy

Agree, that's opposite of what would normally be seen. I'm thinking you have a gauge or sender issue or maybe the thermostat is not installed correctly

 

[truckboss]

open system.Everything is hooked up properly new thermostat.I"m thinking either bad sender or low water flow at idle speeds.Anyways i pulled the exhaust,risers off and all clear.Pulled the sea water pump off,not perfect but looks ok.I"m going to put a new pump on just in case.