Overheating, again

[Wave34]

Volvo Penta 5.7 Gi-D
The boat was running well for many years.

Spring 2021, first ride, overheat.
After troubleshooting, found a bad seal in the RWP. Replaced and ran well all summer.

Spring 2022, first ride, overheat. Troubleshoot, change again the RWP seal. There was rust on the shaft
After reacement, ran well for the whole day on the lake.
That was last week end.

Today, overheat again.

Wondering if the seals get damaged by a bad shaft?
I checked for a new pump assy and it is $670 CND plus taxes.

So I want to be sure before replacing it.

I disconnected the output hose from the RWP while on the lake and started the engine and there is a flow of water coming out.
I don't know if it is enough though.
I have a video that I will try to upload.

Any idea?

 

[KJM]

I'm no expert, but that looks like plenty of water coming out of the pump. Are you sure there is not something clogging up the passage ways in the engine, or maybe a thermostat that won't open properly?

 

[Scott Danforth]

The pump is a Johnson F5B

johnson f5b-9 pump - Google Search

www.google.com

 

[Wave34]

Update.
Thermostat was bad.
It is a new thermostat that I changed 3 years ago (non Volvo) so it was the last thing I suspected.
I'm lucky that I kept the old one in the boat ... It was good, but changed as preventive maintenance.

So, if it ain't broke, don't fix it LOL.