RE: Dang Bubbles
Some bubbles are unavoidable. You may have some other problem. with the tank about 1/4 full, start the engine, advance it to full throttle and hold it straight up for ten seconds or more. while holding it straight up, watch the fuel line going to the carburetor. If there's a stream of bubbles, something's wrong with the tank or plumbing.
If the engine quits when you hold it straight up at full throttle, the main needle valve is too lean. Open it up 1/4 turn and repeat the test.