[Public-List] Raw water system trouble (blockage, stuckage?)

[Andy]

Howdy Folks,

I am having some issues with my raw water system.  Water is not getting
through to the exhaust. At first I figured the pump, replaced the impeller,
that didn't work.
So, next in line, heat exchanger. Took that apart, it was a bit gunked up,
but not awful. Completely cleaned it and rei-nstalled with new gaskets,
surely that was it. Nope, same problem.
Checked the next hoses, the ones with vacuum breaker, no clogging there.
Next I ran the engine with the pump just going from a bucket to a bucket to
see if moves water. The pump seems to work fine. but when I hook the output
back to the heat exchanger (I kept the intake in the bucket to be able to
see if water was being moved) little or no water is pulled from the bucket.
After that out of curiosity I decided to pull pump to heat exchanger hose
off the exchanger and was greeted with a small blast of water to the face.
Pressure buildup from somewhere.
This is a diesel by the way, Yanmar 2 cylinder, fresh water cooled.

Help!  Does anyone have any ideas?

Thanks,
              Andy Shaw
              #477 'Savannah Rose'
               St. Mary's River, MD

 1335035024.0