RE: Vagabond Problems
Paper- Some years ago, I built a Paul Plecan 'Simplex' from Model Builder plans with a K&B .20 Sportster engine. At high throttle, it would do the same thing. At idle, it would glide forever. I cured it by going to a 12X6 Master Airscrew 'Antique' prop. The little K&B wouldn't turn over 6,000 RPM with that huge prop, but I could fly all day on just a few clicks above idle.
I hope this might be of some help- Jim