Water temp gauge

[Tail_Gunner]

The temp gauge has taken on a new life that is when at idle it run's a solid 165 no bouncing rock steady as it always been. Now when I go on plane it drops to 120...3500 rpm and above. Ive replaced the sender unit with the exact same result's. The engine and riser's do run cool and I can see and feel good water flow thourgh the hose's.

A few years ago I did blow a impeller and it thought I caught all the vane's...did I miss one and now it has finally blew out.....Wishful thinking I am sure the burning question's before I tear thing's up can a boat engine do such a thing cool down that is under high rpm. As to the thermostat it's working the boat will not run 140 at idle with no thermostat so any quick thought's????

I guess I should also note that when punching it above 3500 I get a momentary bog with the tbi ..this too is new....

 

[Lou C]

I'd think you either have a piece of rust keeping the thermostat from closing, or a piece of old impeller in the bypass passage in the thermo housing.

 

[Lou C]

I'd think you either have a piece of rust keeping the thermostat from closing, or a piece of old impeller in the bypass passage in the thermo housing.