Super Tiger 45 Problem

This engine is about 4 years old and used to run fine. Now when I run it up on the bench, adjust the hi and low speeds so they are perfect, run it at
low speed for a few minute to insure it doesn't load up, taxi it around, and then try to take off it continually sputters, loads up and stops on the take off roll or just when it gets airborne. Two planes have been lost Can anyone figure out what is going on?
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Ted shuffled out of his cave and grunted these great (and sometimes not so great) words of knowledge:
Since it runs good on the bench (I presume a separate/different fuel tank and lines ) I would check/replace ALL the fuel lines including the line(s) inside the tank. While you are at it, since the engine/plane/fuel system is several years old, I would also check/replace the tubes going through the stopper. Make sure you also check the backplate and gasket to insure they are tight, the O-ring gasket under the carb and the O-rings on the needle valve.
It sounds like you either have an air leak OR there may be some crud in the tank that is blocking the clunk.

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Watchur6:
My first suggestion is to Check and makes sure you don't have air bubbles forming in the tank at all speeds from Idle to Full open. If there is no problem here replace all the fuel lines, in side the tank as well as to the motor. Make sure that your clunk is moving properly, then adjust the carb settings with the fuel tank only half full. My guess would be that you are using a different tank in the plane than you are on the bench, and with the engine and tank in the plane the amount of vibration's reaching the fuel tank will increase considerably. When you say that is sputter's on taxi and just after take-off and dies are you sure it isn't sucking air, Sucking air does not necessarily mean and air leak, but if the vibration's are causing you fuel to foam those little bubbles in the fuel line are the same thing. make sure all your fuel line connection's are tight I've had a few where it was necessary to you small nylon wire ties around the fuel line at the nipple.
Best quick fix I can come up with check things out and let us know what happens.
tomb
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