Engine over heats

[Paradise pontoon]

Those can crack esp if water was not drained out in winter.
The other thing that can cause trouble is the water tube grommets in the lower unit

Thanks I have one on order. I’m replacing everything that has to do with suction side

 

[dypcdiver]

The Plastic Nipple No.9 with the boat at rest is well below the waterline, so would not cause a lack of flow until the boat was on the plane.
I blanked off the outlet from the raw water pump and pressure tested via hose No. 18 to 15 psi with no leaks.
I ran 2 x clear tubes from T'stat housing to manifolds and observed gas in the lines. Se results attached.

 

[BRICH1260]

A couple possibilities that have not been mentioned. First, if you have the blue flush cap on your engine, check to make sure the cap is tight and not allowing air in the system. Secondly, check the O ring on the seawater pump to make sure you do not have two O rings installed, stacked on top of each other. Both will allow air in the system and you will lose suction.

 

[Lou C]

The Plastic Nipple No.9 with the boat at rest is well below the waterline, so would not cause a lack of flow until the boat was on the plane.
I blanked off the outlet from the raw water pump and pressure tested via hose No. 18 to 15 psi with no leaks.
I ran 2 x clear tubes from T'stat housing to manifolds and observed gas in the lines. Se results attached.

I still have the hoses in my spares bin on the boat from when I did that test. Not only will it spot intake leaks in the cooling system, it can also show leaky head gaskets because the exhaust gas gets into the cooling water flow...

 

[HiWard]

Does your power steering cooler have an extra hose barb blocked off by a rubber cap held on by a hose clamp? Could be a potential for a leak.