Nothing but a drip from the fuel pump

[Bitmess]

1975 Mercury 500 50 HP.
I have removed both fuel lines. When I pump the bulb I get fuel on the inlet side of the fuel pump but not on the out. When I try to crank the motor all I get is a drip on the out side. I've opened up the fuel pump, nothing looks really clogged.

 

[Bitmess]

Re: Nothing but a drip from the fuel pump

We looked at a diagram many times and it appeared that we had the fuel lines connected up properly. On the side of the fuel pump one connection says IN so we ran the line from the tank to this one. This agrees with the diagram also. The motor won't run connected like this. We switched the hoses around and it fired right up, Apparently IN means out to the carbs??? Could the check valves be in backwards?
I'm confused.

 

[Chris1956]

Re: Nothing but a drip from the fuel pump

It very much souds like the check valves are in backwards.