Replacing water water intake screens

[AdamLein]

We've got the lower unit on our 1990 Evinrude 9.9hp (2-stroke) removed while investigate and repair the cooling system (more on that later). One thing I noticed was solid particles of various sizes in different parts of the cooling line, some I would even describe as "large-grained sand" or "small pebbles", along with something that I'm pretty sure is some kind of barnacle. It looks like part of the screen on the raw water intake on the lower unit is gone and allowing particles in. I had a look at the impeller and its housing which fortunately are both still in great shape. However part of the aluminum casting in the lower unit below the pump housing was basically eroded through (repair underway).

So I'm looking to replace the screens. I'm thinking of using the screens from a screen door patch kit since I imagine it will be cheaper than buying replacement parts, but can anybody think of a good reason not to do that? I'll probably be using fiberglass screens.

The motor is operated in the usually salty and often brackish waters of the Pacific Northwest, which is almost always teeming with life.

Thoughts?

edit: yeah obviously the topic should say "raw water", not "water water".