Only runs when fuel hose is disconnected

[Seanbono132]

I have a mercury 9.9 2 stroke and it only runs when there is no fuel hose connected to it. I can pump the ball and then disconnect it and then it runs until it uses all the gas in the system. As soon as I connect the fuel hose it stalls. It kinda seems like it is flooding it because when i connect the fuel and it stalls, gas comes out the air intake. I throughly cleaned the carborator already. Fuel take vent is open. Any suggestions would be appreciated. Thanks

 

[MarioTwins]

Vent on the tank open ?

 

[Seanbono132]

Yup

 

[roscoe]

Float in carb may be stuck.
Time to clean/rebuild carb.

 

[Canufixit2]

Ok I'll try a long shot. Fuel pump diaphragm is ruptured. When the hose is connected the gas gets sucked through the diaphragm and into the vac hose/engine flooding the engine. ???