Cd18 b61 55hp new impeller no water flow

"Installed recommended 18-300

"Installed recommended 18-3001 impeller in my
5.5 hp but engine overheated from no water
flow,even with thermostat out.
Took waterpump and driveshaft out and turned it
with a drill in a bucket of water;had volume of
water about 2in. high at housing outlet and when
I put put my thumb over outlet I felt no pressure
and water came out around driveshaft.
Housing and bottom plate look excellent and
parts list shows no other parts in housing,it's
like impeller is to thin and water leaks over on
top of vanes.I am thinking of making a sheetmetal
plate to help seal blades as they sweep .
Am I missing something or dealing with after
market parts that are not exact replacements?"

"ur imp is prob,not ur prob...

"ur imp is prob,not ur prob...ck to make sure,the imp still has the pin that drives the imp..dbl ck the imp number for ur eng yr.correct imp and u should not have to make anything.make sure rubber grommet is in good shap on imp hsng,make SURE u r stabbing wtr tube...many people have probs w/that."