Maxijet+Sureflow upgrade problem

[hillbillyreefer]

Mine were doing that too. I took a piece of airline tubing and filled the gap on the shaft between the propeller and endcap, not too tight. Solved the problem, and it ran like that for several months. I took it apart to clean it a week or so ago and forgot to put the tubing back on, it is still running properly. It's almost like they need to break in or something.