Question:

[reelapeelin]

Originally Posted by Destroyer

and the impeller is made of some kind of hard plastic.

I'd go w/a softer material over hard plastic any day...there is no give w/the harder material, so more prone to nick the edges as sand and other hard debris are pushed between the impeller tip and the housing...chinking away the edges will eventually lead to loss of pressure/volume...

In a perfect world where nothing foreign could get into the pump, maybe the harder material wins, but for real world use, the softer rubber's gonna offer better/longer performance.

On a global basis...I'll be willing to bet there are more (many more) rubber impellers out there in use than harder nylon...and that's because, I think, one word...reliability.

[Destroyer]

Originally Posted by reelapeelin

I'd go w/a softer material over hard plastic any day...there is no give w/the harder material, so more prone to nick the edges as sand and other hard debris are pushed between the impeller tip and the housing...chinking away the edges will eventually lead to loss of pressure/volume...

In a perfect world where nothing foreign could get into the pump, maybe the harder material wins, but for real world use, the softer rubber's gonna offer better/longer performance.

On a global basis...I'll be willing to bet there are more (many more) rubber impellers out there in use than harder nylon...and that's because, I think, one word...reliability.

Really, I don't know what these impellers are made of, I just know that when I hold it in my hand it's hard, and it's not metal. Nor is is Bakelite or any other fibrous sort of material. It looks like nylon, but for all I know it's ABS plastic or some variable in between. All I know is it's hard, it's some kind of plastic, and it works. I't's the only type of pump that British Seagull Outboards used throughout their history. And even though they are no longer made, they are still very much prized outboards, especially by sailboat owners as a sailboat outboard for moving through dock areas, etc. I own 2 of them and can attest to their claim as "The best outboard ever made". They are reliable, simple to operate and fix and are ideal for rowboats, sailboats, etc. And I've never had to replace either impeller in the ones I own from sand, debris or anything else being ingested into the engine, even though I use both of these outboards in rivers and lakes only and have kicked up tons of sand, mud, leaves and twigs and crap over the years. All I can tell you is that they are centrifugal pumps, and they work.