This is a common problem that I see much too often.
There is no need to prime the oil pump after replacing an oil tank, just fill the oil tank about 3/4 of the way up then start the engine on a hose or in the water and loosen the fill cap on the tank to fill the rest of the way while purging the air from the lines.
Snug the cap on the tank when full being careful not to over tighten as it will strip the threads from the tank.