After you check out the ign. system, you can check out the flow rate on the pump, (disconnect the ign. system, unplug the coil, etc.) put a fuel hose on the line coming from the pump to the carb, stick it in a quart jar. See how much comes out when you crank it over. Also, you said you think the fuel filter is ok, do you have 1 in the carburator, as well as before it ? (Just incase , I know many people don't know of the 1 in the inlet on those carbs...)
