1978 johnson 35hp. replaced water pump, and its still not peeing.

yet another case of the famous water pump replacement, and nothing happening.
ok so here is the run down.
when i got the boat it was not peeing. i replaced the water pump assy with a kit that included everything. the housing, the pump, and all the seals ect.
the impeller that i removed had melted into the housing so clearly it was bad. i re-installed the water pick up tube, and impeller housing extension correctly(like 15 time) as to thats how many times i re-checked my work, and still nothing. i removed the cylinder head cover, and found no thermostat, but yet it shows a t-stat in the parts diagram (78 35r78r) model number. i used a garden hose, and put it where the t-stat would go and back flushed the motor. i got water out of all the right places with no issue.
soooo.
would the water pump plate need to be installed a certain way?
im using rabbit ears for a water source.
the thermostat is missing.
i did find debris out of the 90 degree overboard indicator, and removed it.
fishing season is at its peak here in alaska, and im missing out guys. any help would be great. thank you.

fast replys. thanks guys. the old impeller was all intact still, just melted. but i will check that out. it is all very clean on the inside. looks like its only seen fresh water, and or taken care of pretty well. i actually installed the impeller into the housing, removed drive shaft, and installed it that way. the new key way design was a bit of a pain.
i hooked the hose up to the pickup tube, and it was flowing just fine out of the tall tell.
could the t-stat not being installed cause a lack of sealing that will not allow the water pump to create enough vacuum to prime itself. hahaha. crazy talk i know.

very good idea sir. i will give that a try 2maro and see what happens. thank you.

alright. figured it out finally. the grommet at the top end of the water pickup tube had been overheated by previous owner, and the tube was going to far into it, and not sealing properly. yay.
ive got a total off the wall question tho. have you herd of, or have any recommendations as far as robbing power from the stator to a transformer to add additional power to the boat?