Water pump

[mrford]

Hi nuby to seagulls just got the nicest most beautiful 40 plus SJP 301 M4 put it in water 2 pulls and it runs well !!! No water at the tell tail . I put the hose on the tell tail hole to back flush no help took it out of the water out the hose on the intake of the pump and water came out of the drive tube holes . So i took off the lower unit I think the copper tube was in the hole but not 100 % sure . The impeller is 3/16 s shorter than the housing . I don't like this am tempted to make one taller leaving some room maybe 1 /32 inch than 3 /16 inch . I blew air up the copper tube and it came out the tell tail and when I plugged the hole it held pressure . Its to simple not to fix my friend said take off the prop may be it was not deep enough I had water only to the gasket line on the lower unit guess the impeller was out of the water ??? You guys know best what do you think ??? Vic Thanks HELP