Bill,
Good idea about bench testing. I just happen to have a brand new 8 ounce tank that I could experiement with. This engine did this even when brand new in this plane. I attributed it to it being a poor quality engine, but so many people here like the GS40 and don't seem to have similar problems. I only have a 10x7 for this engine. Is a 10x6 better for breaking in? LEss load?

MIke