ORIGINAL: backyardkevin
i had a evolution well istill do actually but it was a .40, came with my plane and never ran from the first try out of the box. would not take any settings lean or rich and acted very strange. it would start up and would run all day long at low speeds but as sooon as you hit it wide open, it would either die or would run good for 10 seconds and then bog and just go back and forth. I tried different plugs, i checked for leaks and nothing, same thing. i changed to different tank (same thing).i took it off the plane and mounted it to a stand and no matter what i tried it still done the same thing at high speeds, would go in and out from slow to wide open but never would really let loose of all it had, i gave up i took it off the stand and put it aside and now am running a dependable O.S. 46 LA. at least i can fly now!
thanks!
I have a Webra Speed 40 that did the same thing. It would idle all day and run fine on the ground. But as soon as you took off and was at the point of no return it would quit. I had the needle valve opened to the point at which it was just hanging in there do to pressure from the adjustment tab and it would still die on me.
Obviously this wasn't right so I took the intake needle valve apart and it all looked good, you could see light through everything and get air through the places you couldn't see.
Come to find out I had a piece of paper towel that I had used to clean my plane, that had became stuck in the intake nipple and everytime the fuel hit it, it would swell and close down on the fuel. I found this piece by sticking the back end of a sewing needle in every opening.
I use a 60cc syringe to fuel my plane. I had laid the syringe on the piece of towel and the wet end gouged a piece out and unknowingly I injected it into my fuel tank.