I just got back from the flying field. I am new to this sport. When I have my plane on the bench and run it at full throttle for a bit my fuel line to the carb turns to nothing but bubbles. Since I have to let it run at WOT for about 30 seconds I am suspecting vibration is causing this. The tank is not foam mounted and from the looks of things there is no way to add foam around it. Would a pin hole in the fuel line cause this? Would a uniflow setup cure this problem? I need help?

Thanks

In my experience bubbles in the fuel line are a result of a poorly pressurized fuel tank. Check that the seal is secure, and you are getting good pressure from the exhaust nipple. Also make sure the bottle itself is not damaged.

Last time I had this same problem it was just a cut in the fuel line that was letting in air. It was between the remote needle valve and the carb. I cut it while tightening my engine down in the mount.

Kimhoff,

There is a thread here on breaking in and tuning engines. Do searches on these words and I'm sure you'll find what you're looking for. The best thing to do at this point is to find someone near you who is experienced to assist you. You're going to get a LOT of advice here that may be a bit hard to decipher for a newby.

Good Luck and Welcome to the Addiciton!

G~

> The tank is not foam mounted and from the looks of things there is no way to add foam around it. <

Is the problem that the tank is so large that there is no space to add foam? It that is so you can buy a tank in a different size or shape that should have a smaller cross-section which will provide space for the foam. Sullivan has a large assortment of tank types at www.sullivanproducts.com/

A uniflow can cure some kinds of problems but not that one. A pin hole leak can do it in the fuel line either in the tank or outside the tank. The pin hole would be the first suspect not vibration although vibration can sure cause it.