This one can be answered by DA directly. Tell them the symptoms with as much detail as possible. I'd give them a call. You'll have to wait until monday and it may take until tuesday to get them on the phone. The phones are very busy there at DA...for obvious reasons so be patient. You have to keep trying and keep trying until you do get though. I'm sure they can tell you what is going on. If it won't run at factory needle settings I would leave it alone until you find the cause. It should start and run. IGN engines (especially DA's) are not finicky unless something is wrong in the setup. Check you lines...be sure there are no air leaks around the lines and that they are secure. Make sure any filters are not clogged. If you are using a small hobby filter chuck it and get a big weedeater size filter. It has to flow. Make sure the line is at least 1/8th ID and that the tubes on the tank is 1/8" ID...at least. i use the large 5/32 and 5/32 line. I also use Easy Flex gas line from Aerotrend. Make sure you vent line is clear and not plugged as this will cause the carb not to pump fuel. Take the spinner and rock it back and forth bumping it against compression on both sides until you see fuel coming up the line...it should move about an 1/8" at a time everytime you bump compression and the diaphragm pumps. Check your IGN battery. Don't just load test it...check it under load right after the engine has been running...especially if it is a 4.8 v NiCd! It may not have enough energy to keep up with the current demand of the IGN. This is why I use Duralite Plus's with regulators. The voltage will stay up from first flight to last. Remove Plug and touch plug to cylinder and flip prop with authority to see if it is sparking good. You should see a good blue spark. If it is orange or wimpy there could be a problem with the IGN although this would be highly unlikely as the DA IGN's are probably the best on the market. I feel pretty certain it is something simple, but there are alot of simple things to check. I bet I could get that thing running like a top in less than 10 minutes if I was there. That's another idea that just popped in. Get somebody that has one of these or somebody that's run DA's to look at it or an Unlimited flier or 3d pilot or just somebody with alot of hands on. The IGN engines are very reliable. There really isn't much that can go wrong mechanically with them as they are a great engine and are designed right. It's just about gotta be something in the setup somewhere.