Jim,

Its hard to guess without seeing the machine just what might be the problem! Start at the rotorshaft and work up. How are the bearings? Insure there is no binding and lube the bearings with some Marvel Mistery Oil. I never tighten my blades on the hub too tightly. They should be free enough to seek their optimum lead/lag angle. Inspect the blades carefully to be sure the airfoil is fairly accurate. It is also important that the blades all have about the same airfoil. Also make sure the blade surface is smooth and shiney.

If all of the above don't do it, try adding a bit more negitive incidence to the blades. I was able to get mine to spin up using just a large box fan!

Good luck, Let me know what happens!

Randy