On Thu, 2 Oct 2008 23:08:53 -0500, "justme" wrote:

I have a small cast iron, gear pump that was working.

The gear is about an inch in diameter, .375 thick and the other gear (idler
type) is a bit smaller.

No blockages, no clogs, all looks good. However,
there are three set screws/plugs around the periphery of the pump
equidistant at 120 degrees.

This thing no longer pumps but tries to do so.

There are no leaks. I did fiddle with the plugs as it was not doing well.

Help, anyone?

Are you spinning it in the right direction? The oil goes around the
outside of the gears and the meshing gears pushes it out the outlet
instead of letting the oil just go round and round and round...

Hidden check valve? STUCK hidden check valve?

Liquid too thin? Water and light fractions like gasoline are not
meant for gear pumps.

-- Bruce --