Rising temperature on starboard engine

John41

Both of my engines usually run at 175 degrees. The past couple of weeks I noticed my starboard engine temperature rising above the 175 when I’m driving the boat. If I back off on the speed it tends to come down. My antifreeze looks good. When I touch the impeller it is cool. Any ideas what could be going on?

LaRea

If the metal surfaces inside the pump get worn or scored, the pump will start to lose efficiency.  The only way to find out is remove the impeller and look inside the pump.  

YYZRC

Could also be a sign that your risers are reaching the end of their service life. 

raybo3

Try taking off the end caps of the heat exchanger and cleaning the tubes and the area around the end caps. Very little debris can cause that problem and very easy to do. 

aero3113

I think it sounds like you’re impeller housing and impeller need to be looked at/replaced. Are you in fresh or salt water? Do you have dry joint or wet joint manifolds? Being that you have antifreeze running through, your manifolds should last a long time. There can also be a restriction in one of you hoses causing the overheat at high RPM’s. As @raybo3 said, a good place to start for that is your heat exchanger.

tricountytrail

Agree with all above.
I had same problem here is what I found.
Port impeller was new but housing all grooved new pump on its way.