Udi, check the pich of all blades first by placing an approx 3' straight edge from the back of the blade to the floor and make a chalk mark. Do this with each blade in the same position without moving the machine.
I have a prop balancing gadget that I use for multi blade props so I will take a pic and post it hopefully tomorrow. The old pic is a millin words when you a slow typist like me!!!! Aussie Paul.