Well, a .91 spinning a 14 inch prop, pulling around what is likely a 4.5 to 5 lb 40 sized 3d plane will probably not be able to slow down enough to land under power! One of the issues of overpower a plane with such light wing loading a superior lift. Might just have to kill it to land everytime!

However, you should be able to idle down into the 2000's. I have two of these engines, and they all idle pretty low. But, they don't come with a good plug, so change it to a good one--OS F or H9 super plug and you'll notice an instant difference!