1965 johnson 40hp HELP

[walleyewonder]

My motor isnt cooling the impeller is new the housing is fine they key is grabbing the impeller water is filling into the system but wont get to the exhaust. removed thermostat and can pump water and it falls out the intake what am i missing??
maybe a peice of the old driveshaft stuck blocking it
cooled before driveshaft was replaced but not well.

Please help