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

Fuel admittance needle (operated by regulated membrane) is sticking, or there is no pulse to activate the internal pump.

Thanks for the quick reply. I manually opened the fuel admittance needle earlier today, if its the one on top of the carb(inverted engine) while blowing on the fuel line and fuel does comes gushing out of it as long as I manually press down on the fuel admittance needle while pressurizing the fuel line. It appears to work fine manually and doesnt appear to be clogged. It looks like the needle is opened by the metal pin that is attatched to the membrane. Do I need a new membrane possibly?

In that case you seem to be lacking fuel pressure.
Check the pump and pulse line ducts, (no fill line in carb fuel suction line please!), open both needles 1.5 turn from closed to get a running start so you can get the engine to run and set the needles.

I will check the pump and pulse line ducts tomorrow, I assume they are both on the bottom of the carb. Thanks for your help

If the the engine has been run for a while, the problem could be that the tiny fuel passages (three of them) from the low needle to the venturi are blocked (partially). The only good method to clear them is to remove the welch cover, run some thin music wire through them, and install a new welch cover.

I have experienced the fuel-drawing problem with my D A50 and ZDZ40 a couple of times. All were caused by passage blockage. Once they are cleared, the carb returns to normal right away.