I'm using a 22X10 Pro-Zinger prop on this engine. It has a smooth transition from idle to full throttle (runs smooth at full throttle). When in idle, on the ground, it idles very rough. Is this normal for a BME 50? I have this engine on a GP P.Wagstaff extra 300 and when in idle, the whole plane really shakes. The wings and horizontal stab are just fluttering away like mad. I think this just plays havoc on the servos. Idle RPM is 1300 to 1500 and when increased by 200 RPM it will smoothen out but then I'm idling at 1500 to 1700 RPM. I may be wrong but I would think an idle speed of 1700 or 1800 RPM is too fast. Has anyone out there experienced the same problem? I welcome any comments and suggestions. Thanks.

It's not too fast if the plane doesn't keep moving...Almost any single cylinder engine will shake at really low rpm...A heavier prop might smooth it out at the really low idle speeds..

It's possible your low end is too rich. Try leaning it and see if it smooths out. When it's too rich it only fires every few power strokes so it really shakes. When it's leaner it will fire almost every power stroke and it will be smoother.

I saw one in a Midwest 80" Extra 300. It was the smoothest 50 I have seen to date. It prompted me to get one I have never seen a 3W 50 run so I can't compare that engine.

So far no one has noted the level of balance with the prop. Just how well is it balanced? Also of note is that Zingers flex quite a bit, adding one more type of vibration to an engine.