Hi All

Thanks for all the good advice.

Let me give you an insight in my dilemma. I am building a H9 Twist 150 and want to fit a gas motor. The tank come with a nitro stopper and the manual say you have to replace with gas tubing and stopper. I have about 5 Du-Bro stoppers in my drawer, but guess what, they are a bit to small for the H9 tank. I do have a black stopper that is the same size that is supposed to be a gas stopper as it came with a 50 cc gas Chinese YAK, but I want to be sure before I use it.

I will take Pat Roy's advice to soak it in gas and see what happen.