My last trip of the 2022 season I was idling around trying to find a spot to fish and the overheat alarm went off. I did what any reasonable fisherman would do and dropped anchor and fished for a few hours! 
When I pulled anchor and drove back to the docks the engine never over heated.
So this spring I:
First trip out this spring it happened again putting out from marina in a no wake to open water. I realized if I throttled to a few hundred RMPs higher than I was running through the no wake the temp goes down. And cruising on plane the temp stays at 160.
So I pulled boat and:
With the lower unit still removed and the water return hose still disconnected from the lower part of the engine, I put a garden hose directly on the water tube and turned hose on full blast and water never came out the return hose. The water basically comes out of the driveshaft housing aft of the water tube. If I let the water run long enough it eventually pees but sort of weakly.
My main question: injecting water into bottom of the water tube, shouldn't water easily be be reaching the thermostat to where I'd see it exiting the water return hose?
And if it should, which it doesn't in my case, it sounds like I have an issue with my water tube or its connection with the powerhead.
Any thoughts?
When I pulled anchor and drove back to the docks the engine never over heated. So this spring I:
- replaced the thermostat (old one was corroded with white crust) I'm in sound off SE CT / RI
- performed a complete water pump kit install
First trip out this spring it happened again putting out from marina in a no wake to open water. I realized if I throttled to a few hundred RMPs higher than I was running through the no wake the temp goes down. And cruising on plane the temp stays at 160.
So I pulled boat and:
- Dropped lower unit to double check the water pump install
- replaced the rubber bushing at the top of the water pump even though the old one seemed fine but thought it might have a little slop
- Back flushed the engine through the water return hose into the thermostat housing (with thermostat removed of course) and water flows out the water tube just fine (lower unit obviously was still removed)
With the lower unit still removed and the water return hose still disconnected from the lower part of the engine, I put a garden hose directly on the water tube and turned hose on full blast and water never came out the return hose. The water basically comes out of the driveshaft housing aft of the water tube. If I let the water run long enough it eventually pees but sort of weakly.
My main question: injecting water into bottom of the water tube, shouldn't water easily be be reaching the thermostat to where I'd see it exiting the water return hose?
And if it should, which it doesn't in my case, it sounds like I have an issue with my water tube or its connection with the powerhead.
Any thoughts?