I have a husqvarna k750 which has new cylinder, piston and rings and new crank seals. It will run if you squirt fuel in the sparkplug hole but it does not seem to suck the fuel up from the tank. The fuel filter is new and fuel is getting to the carb when I take the line of f fuel runs out of the fuel line. The diaphram is good in the carburetor and when you press it down carb cleaner goes through the needle and seat fine. There is a hose that is fine which goes to 2 connections on the carburetor. I think that is for the fuel pump system.