Dual fuel tank problem

[smokeonthewater]

To get down to brass tacs...

The fuel starts at the pickup in the tank and flows through the hose, valve if equipped, any fittings, squeeze bulb, etc to the motor....
If it is plugged OR has a leak anywhere in that path it won't work...

Start at the beginning and follow it's path, testing each component until you find a problem...

Also a plugged fuel tank vent can stop fuel flow but would be obvious if you open the tank and is pulls in a bunch of air.