Have an inverted .75 Tower engine on a UCANDO. Set needle to 4.5 turns out for first start...per factory instruction. Has cowling, and external fuel dock, and I have the Needle valve at a remote location (though I did try it at factory location). Both lines are hooked up correctly. Tank fills just fine. The problem is that in order to keep the engine running, I have to pinch/ restrict the exhaust port in order to produce enough back pressure to pressurize the fuel tank and get the fuel flowing to the carbeurator. The tank is preset to the correct height and appears ok relative to the carb inlet. The minute I take my hand off the exhaust, the engine sputters and dies. My thought is that there is an air leak... also checked the tank and the fuel and vent lines are in the correct orientation.....just not generating the pressure.

Anyone have any suggestions?

Sounds as though there is a restriction in your fuel line between the clunk and your needle valve. There's a hose kinked or your docking station is not right or something?

There's a couple of the Tower 75's up at Willard and I never saw them have any problem.

Good luck,

Jim

You may have the idle mixture set a bit too lean. If the idle's a bit lean, it can interfere with high-speed fuel flow. Open the low-end needle a LOT, get the engine running at part throttle and then open the throttle to full. Set the high-speed needle so that the engine's running just rich of peak RPM. Now set the low-speed needle as necessary to get a reasonable idle. Anything below 2,500 is OK. If you try to idle too slowly, you can also get transition and midrange problems.