HOW CAN I eliminate THE BUBBLES IN MY FUEL HOSe? i spend my complete sunday at the field trying to get my little mustang 46 evolution to run right and then i realize that i have bubbles on my fuel line! i thin this is the problem

One of two things are the most likely cause.
Tank is mounted to firm, vibration transfers to the fuel and makes bubbles. Mount the tank loosly in foam.

There is an air leak somewhere between the clunk and the carb. loose fiting fuel line from tank to carb or a small hole it. Same for the tube inside the tank, the smallest hole that you cant see will do it. If you have to, and if you can, put the whole tank and lines in a bowl of water, plug one line and pressurize the other line to spot the leak. Could also be a hole in the tank. If your sure the tank is ok, replace "all" the tubing.

I had the same problem on a TH 61. I used the little zip ties to secure all the permanent fuel line connections, including inside the tank, and it stopped the bubbles. The only connection that doesn't get a zip tie is between the tank and the high speed needle that I use for fueling.

thank u guys .

costarican pilot,

All the above info & hints are true. Try and convince yourself to take nothing for granted. The root cause can be a simple issue like too large a size silicone tubing. The connection of the tubing to the carburetor if it is too large, air may leak in to the fuel line and cause bubbles. Make sure the fitting on the carburetor is tight, also check your exhaust pressure line inside the tank, it should be bent towawrd the top of the tank. If it is bent the wrong way (downward for example) it will bubble & foam into the fuel tank. This last one is a bit of a push, but check it anyway after you follow the advice above you will fid it. Be patient, and be determined to not assume anything is Ok unless you check first.

Sledge_78

When assembling a tank try soldering on the Dubro barbs, they come in several sizes and are cheap, they will keep your lines from falling off. Try using fuel line over fuel line to attach your lines to a tank. This doesn't work usually for any lines that need to be removed to fill or empty a tank, it really makes a nice tight fit. After you assemble a tank check it buy pressuer testing under water. A hole in the lines either inside the tank or outside the tank will cause bubbles. A pressure line inside the tank that is upside down will cause you to not get a full tank of fuel.