150 hp Mariner Magnum "water" issue

[bassn4$$]

My brother bought an 85 373V with an 85 (I believe) 150 hp Mariner Magnum. First thing we did was drop the lower unit to change the impeller. It was toast and burnt, housing looks fine but lots of rubber melted in the housing like it had been run out of water or plugged. We ckeaned this out there was no scoring and everything looked as it should after we were done. I checked the stats and they all opened right at 140 (out of the motor on the stove using a themometer) and look clean. I ran water up the tube in the stump with the stat out and housing off and it fills up nicely. Now we put the lower unit back on hook the boot up and start it with the port side stat out (not hooked up up and discounted from the head) no water is going in. Boot on the lower unit, off the motor and clear of any obstruction, and it's coming out like it should. Tubes are properly aligned when the lower unit is put back on sooooooo WTH?? I'm stumped please help and thanks in advance.

[EuropeanAM]

Pull water pump apart and confirm that the IMPELLER DRIVE KEY is properly in place.

Also, verify that there are not pieces of an old impeller BELOW the water pump impeller plate/base, down in the passages for the water inlets, etc.

Very wise to install a COMPLETE water pump kit.

[bassn4$$]

Its all clear removed the debris but the drive key I never even thought about but thanks for the input and the price for advise is right! Thanks again