Doc:
Is the fuel pump mounted externally, meaning not inside the carb, maybe on the side of the engine with one hose connected to fuel filter (which connects to tank), one hose to carb fuel inlet, and a third hose to engine crankcase? If so, it is an impulse-type fuel pump. Troubleshoot by removing line to carb at fuel pump, remove impulse/third hose at crankcase and alteranately suck and blow in line you removed from crankcase (should be dry/no gas, you are on the air side of the diaphragm, imitating "ipulses" in the crankcase), look for fuel coming out of pump where you removed carb hose.
If no fuel when imitating "impulses", then about 3 things come to mind:
1. Clogged filter (but you say not so)
2. Clogged hose to tank or junk at bottom of tank clogging fuel flow
3. Fuel pump itself
You can eliminate 2 of these possibles by connecting a line direct to inlet of pump and putting other end is a can of gasoline and doing the "impulse" imitation again to see if pumping (eliminated filter and tank clog). If not, almost certain pump problem, probably need to replace, but pump itself could be full of junk I guess.
RavensRoost