Carburators are loose

[Wheels]

My 10 hour old 912UL is running smoothly, or it was. I noticed a little roughness a few days ago an inspected to see if anything had slipped in the linkage department.
The number 1 carb had clocked about 2 degrees. that would upset the float condition so I grabbed it by hand and easily turned it back to vertical. I checked the screw on the clamp, I loosened it completely and made certain the carburetor was seated completely in the boot. I tightened it back down and flew an hour to see how things faired. It didn't stay at the 1200 position, in fact I notice both are slightly off. I video taped the engine at idle and at 4000 RPM to see if I could determine a heavy vibration and I don't think its there. I may have to change the shutter speed on the camera to make sure there isn't a lag in the video but honestly, the naked eye shows nothing abnormal either. anyone else seen this behavior before. I"m convinced the torques are good on the rubber mounts and such. I don't want to damage the boot, but they aren't holding up.

[avidflyer]

I think on the 582 carbs, they were supposed to be tightened till there was a certain distance left on the clamp. 8 MM if I remember right. Is there such a thing for the 912? JImChuk

[Av8r3400]

The new engines actually have a spacer in the clamp to prevent over tightening. I'm not a fan of that design.

[Wheels]

I shaved 1 mm off the spacer and reinstalled it. I flew for two hours and did multiple touch and goes and other fun things to wring out the engine at all RPMs. the carbs stayed put.

That spacer was 8 millimeter and I only had trouble with the left one. I didn't touch the right side. (no.2 aft looking forward.) I put on the nose cone tonight, I"m almost satisfied.

[cap01]

thanks for the tip. i only have the issue on the right side.

[Wheels]

I may be wrong but I think the carb was probably turning during start up when the choke cable was being pulled. It would certainly pull in the direction of rotation and the vibration at start up is often quite exciting for the little fella.