I have spark so I ruled out ignition and plug. Fuel runs freely from tank to carb, so it is not a tank problem. I think the problem is in the carb. With the choke on or off the carb does not draw fuel. I have even sucked fuel hafway up to the carb, placed hose back on nipple and continued to hand flip and it still wont draw up into the carb. I even tried pressurizing the tank to try and get fuel into the carb and still no luck. Only thing I did to the carb was to pull the top and bottom plate of carb to take a look and try gently blow some air and fuel through. I found a little gunk in the bottom screen. (yes I have a fuel filter) Reassembled and still no luck priming. Engine has approx 2 hours of run time, 3 flights on current airframe with last flight ending up in a deadstick. I havent been able to start it since. Please help a gas newbie. Thanks