[Tommy]

Regarding the poor running engine - If you are certain there is ample gas at the right pressure reaching the carburetor, and you are certain the engine is running lean, then something must be wrong in the carb. Perhaps when the old pump failed or when you removed the carb something disturbed the floats or clogged up the jets. Check them.

Regarding the fuel pump losing its prime - You said the pump is about 6" above the bottom of the fuel tank. Until you can do a permanent fix, try topping off the fuel tank with gas whenever you will be leaving it for a while. Maybe you can keep the level of gas in the tank higher than your fuel pump.