Thanks for the comments Guys,

I ran into a situation a while back when using a 4-stroke Thunder Tiger on a "Magic". The engine would run fairly good no matter which way the plane was flying or rolling, inverted flying included. My problem always occured when I attempted a high G manauver as in starting into a tight loop. The engine would just die, no cough, no sputter, just die. If I eased it into verticel it would continue to climb
without a problem. I reoriented the engine on the firewall a couple of times just to be sure the carb was not too high or too low in relation to the tank. I finally gave up on the 4-stroke and put a 2-stroke in it and the plane flys perfectly. So, this problem has been sticking in my head - I digging really low trying to figger this one out - thus the one way valve question. [sm=72_72.gif]

Thanks for your thoughts,
Sonnytex

P.S. The tank, clunk, lines ect. were all checked at least twice. All engine possible air leaks were also checked.