Trouble overheating

[Jstone18]

Hello,
I have a 2003 90hp 2 stroke outboard, When I run the motor off the hose with the muffs it runs well and never gets over 130degrees. the water circulates and is coming out of the piss hole, but has a weak stream.
When i take it into the water the boat overheats in about a minute with throttle, and goes into protect mode. I just bought the engine and supposedly the water pump was changed last year, i recently put a new thermostat in.
Any suggestions on what it might be?
Thank you

[Not a mechanic Mark]

water pump

I had the same problem, replaced the water pump, issue resolved. It stays cool under pressure "assist" with the hose, take that variable away and it overheats. Sounds like the water pump in your situation too.

However I am not a mechanic. Before you invest in parts wait for advice from someone more knowledgeable than me. I will be interested to hear what they have to say. Good luck.

[Jstone18]

thank you,
I plan on replacing the water pump assembly, and the pressure control valve.
Hopefully it fixes it, I just hope im not overlooking anything.