I am using an old OS 120 4 stroke. My first time w/ 4 stroke and it is inverted, no pump. I made my own exhaust to fit within the cowl. Before I flew it I ran it up on the ground, the engine is used. It ran good but then I noticed the line going to the tank for pessure had melted off the nipple. I assume I put the nipple too close to the exhaust port { only 1 3/4 "}. The question is do I need to pressurize fuel tank?
Gene K