Follow the instructions on tightening the prop, then go about four or five clicks to the rich side. The prop is spitting off because the engine is suddenly stopping. This is usually from a over lean top end. Being as it is a new motor, it isn't broken in yet and will sieze up if it is to lean. Keep it well on the rich side for at least 30 minutes running Follow the instructions for break in very carefully. The first two ro three tanks are the most critical. Once you get it broken in, don't peak out the high speed needle. You want to find the peak and then back off four or five hundred rpm to the rich side. Maybe a bit more until you have several tanks of fuel through it.

Don