This is a “non-bailer” Scott made motor.
I’ve been trying to get a new Sierra 18-3072 impeller to
work to replace the original, NLA.

It’s the same OD at 1.890, and I believe I bored out the shaft hole
to .500, from .420.
The main issue with it was that it was about .040 too short, so
I removed the liner and machined it down to match the shorter
impeller.

The cover sits atop the pump liner with an o-ring atop of it, and
the seal plate compresses the o-ring, and holds the cover down
tight against the impeller.
Being that I machined down the liner height, I had to shim up the
o-ring slightly so it would compress when bolted up.

I put the motor all together this past winter, and when I got it
running this Spring, it would not pump water.
I’ve been trying to test it out with the gearcase in the test barrel,
spinning it with my cordless drill.
It will barely pump above the top of the gearcase.

There is no obstructions, and the liner can’t get out of orientation.
It looks like it should pump but doesn’t.
What am I missing?

VIDEO……..
https://youtu.be/x0SJQoG7Srg

I machined down an aluminum puck to fit inside the liner
to get the liner machined down even so the liner cover is
touching the impeller.

I shimmed-up the o-ring to be sure
that it compresses and holds the pump
housing cover on tight.