The drive must be taken off to access the plastic insert that holds the hose to bell housing..

You keep saying bell housing ?? the hose goes from the connection on the inner transom plate to the sea pump, a bell housing is a large round object that bolts to the rear of the block and has two tabs that bolts to the inner transom plate to support the back of the engine

the part the drive bolts to is also called a bell housing.

You guys are talking about 2 different hoses.

Anyone give any credence to the air lock theory.
Open cooling is kinda like having a drain cock open on a lower rad hose, it will drain until a vacuum is created unless you have the rad cap open to let air in.

Could my cooling system be doing the same thing when it is out of the water......

the water hose should be dropping to the water pump,not gonna siphon back.
have any pics of the pump and water lines.

you have been told to remove the hose from the intake side of the water pump and then back the boat in the water and check for water running out of the hose.have you tried this yet?

LOL I thought it was a helmet

The pump, hose and spigot on the transom are nearly level, the boat sits with the bow up slightly in my driveway, so it will likely drain.
I live in hill country and it will drain when towing as well.
I`ll get some pics when I have time.

if I kept wiping out impellers,,I would install a sea strainer and keep it filled and high enough to hold water to the pump.

Not yet, work gets it the way
Ran it fine on the hose last night though.