Raw Water Pump Inlet / Outlet ?

[four winds]

Oh man, I get it now. As long as the fins are sweeping back and coming down across either opening. The water flows around the bottom and the ramp squeezes it out the other opening.

Just have to make sure it sweeps down across the inlet and up across the outlet. Either direction will do with the proper connection.

Seems like this means my Jabsco would do the same, as it's a virtually identical design. That's why I found the thread interesting in the first place.

[daddle]

You can't pump the water "over the top". It goes around the long way no matter which way you turn the pump. Most of the water is squished out of the impeller cavities by the cam as the impeller turns. When it gets squished out it leaves by the nearby respective port.

These pumps are remarkable because they are the best pump for the job while at the same time being wholly unreliable. We're apparently stuck with them.

[HopCar]

There is a nice little animation here that shows how a flexible impeller pump works. Flexible Impeller Pumps - Johnson Pump brand - SPX Flow Technology AB
I like Daddles description of the water being "squished out". That describes it perfectly. I do disagree with the statement that they are " wholly unreliable". They will run hundreds of hours before maintainence is needed.