A few things to look at in the water pump. How is the wear plate? If it is grooved it should be replaced. The first picture shows a wear plate in good shape. The second one is grooved and needs to been replaced.

This impeller housing is getting a little worn, but should still pump fine. I’ll put this one backin as-is.

Water tube grommets can get damaged or lose their ability to seal up too. This one suffered damage when the lower unit was reinstalled. It was partially blocking the water passage and not sealing properly.

Hope this helps a little.
-Ben