Weak raw water pressure

[grant.mckenzie]

https://moyermarine.com/product/mmi-...p-csob_00_365/

Hi I have one of the linked pumps on a raw water cooled engine, pump was new about 5 years ago, never changed the impeller. I'd say about 10 hours per year on the engine.

Boat is out of the water, I am preparing to launch. Had trouble starting engine this year maybe a total of a few minutes running the engine in the starter, for most of that time I forgot to have the pump inlet hose in a bucket of water.

Engine is running now, but water pressure is close to zero on the inlet and outlet from the pump - I can put my thumb over it without problem.

I took the impeller out and with a quick inspection it looks very good - no broken vanes or decay of any sort.

Any thoughts? My only idea is to change the impeller, obvious I know...

Thanks.