Early on I hooked up an accelometer to an oscilloscope. It sure was a mess - very hard to discern any fundamental frequency. My conclusiion was that I needed a prop pickup to trigger the scope and perhaps a notch filter so I would only be looking at the fundamental frequency of the prop. I never did get back and try it.

Finn

Perry Mick wrote:

I've used the balancer many times before with no problem on direct-drive. I think it's getting confused by harmonics or beat frequencies between the engine and redrive. For a first step it usually asks for 20-30 grams at a certain radial position, the fender washer is about right. This is on the prop bolt circle (4.75 inches?), not out at spinner diameters. It will just be moved around the six locations temporarily to see if the vibration gets worse or better.

Perry