Thanks Paul. If there is no suction on the port you connect the fuel inlet hose to, either it is the wrong port, or there is a horrendous air leak inside the carburetor. Then you just check the other ports to see if any of them has suction: if one of them does, that is the correct fuel inlet port. Of course you don't even need to connect the return hose if there is no suction on the inlet port, since it isn't going to pump fuel anyway.
