Diagnosing circulating water pump?

[Ck111484]

Having an overheating issue on a '93 OMC Cobra 5.0 Ford.
What's the best way to diagnose the circulating water pump?
NOT the impeller on the outdrive, the pump with the belt on it on the engine itself.
Thanks

 

[bruceb58]

Unless it has an automotive pump on it and the impeller corroded away, it's not going to be your issue.

 

[Sparkinator]

Did you check the thermostat?