I have a merc 9.8 mid 80s. I Started it out of water for about 20 seconds & burned up the pump. Replaced the pump but it is not pumping water thru the motor & out of the little hole at top right of motor. I can put the ears on the flush hole with the hose running & water comes out of the little hole just fine. I have flushed & backed flushed numerous times with air & water thinking there was old impeller parts stuck. I forced water up the copper water line into the motor where the pump would normally pump it, but I cannot get it to flow thru. I suspect something is plugged but dont know where. Any body got any ideas. Thanks for any help