Many times, the low-speed needle comes set too lean from the factory. The "factory" settings on almost any model engine cannot be considered to be in any way reliable. You have to work with them. With SuperTigre engines, you MUST start out with a too-rich low end and a very rich high end. Get the engine running and up to full throttle. After 3-4 24-32-ounce tanks of initial running, you should be able to lean the engine to just rich of peak RPM. THEN you reduce the throttle and work on the low-speed needle.

Going lean during a flight is usually a symptom of a slightly-lean carburetor setting. On SuperTigre engines, if the low-end is too lean, it will affect the high-speed setting. When first starting to work with the engine, there's no such thing as a too-rich low-speed needle setting.

Your fuel tank may be too far from the engine, and the fuel tubing may not be large enough. We use large silicone line and and large brass tubing inside the tank. We usually have to replace all the tubing in the tank to get the larger stuff to work.