I have a YS 63 That was running fine when i put the plane away a couple of months ago. I took the plane out and started the engine it seemed their was a air leak i changed the fuel tank with all the tubing. It starts fine for about 20 seconds but it seems like it is running out of gas. I see air in the fuel line it surges and then dies out. Help. Also what is a good start point on low and high end adjustment ?

Chris

Since you stored the engine and maybe didn't run it dry, plus probably left it hooked to the tank, the regulator needs to be taken apart and cleaned and possibly needs gaskets and diaphragm replaced. The fuel passages may be clogged as well. Before doing all this, try opening the main needle about 3 turns and running it at full throttle for a tankful of fuel. If it dies rich close the needle down and try again until it will run at full for the whole tank. Might fix it.

Thanks Dave I will give that a try. The regulator? Is that the Big Brass Flat head on bottom of engine ?

YES, and it requires adjustment sometimes no matter what you've read elsewhere. It controls the transition from low to high, just like a mid range needle valve.