Hi Walter,

My TSIO 550E with MT 4 Blade had a very strange vibration after engine overhaul that three prop balances didn't get rid of. One very knowledgeable guy asked what prop I had and said that with the light wood blades it didn't have roatating mass or flywheel effect and that he thought I had a plugged injector. I had all the injectors pulled and inspected for dirt before cleaning. They found a small restricting piece in the cylinder that I told him had a higher than normal EGT. That fixed the vibration problem. Live and learn, even at my age.