[fkshiu]

The propellor is spinning the wrong way and is hitting the tab which is designed to make it spin the correct direction. What is probably happening to prevent this is the greater interial mass of the white (bigger) propellor is preventing the proper bounce back. The smaller (black) propellor does not have this problem on Sureflow kits. All the snapping against the tab puts extreme torque on the propellor which will eventually tear it apart. This is why you should NOT use these things on a wavemaker.

How do I know this? Numerous tries on building my own "maxi-streams" out of various bits and pieces before there were DIY kits available along with reading the monstrous thread on RC. The bottom line is that if you get too greedy and push the envelope (i.e. the bigger white propellor on a Maxijet 1200) you're going to run into trouble. Remember, this is - after all - a DIY project. One of my Franken-streams is now the dedicated salt mixer - a job it excels at but makes a big racket doing.

If you stay conservative and use the smaller black prop on a Maxijet 900 it shouldn't give you any problems. I've had my Sureflow going without issues for over a year now.