I had the same problem. Its not the prop. Its the transmission. I found that my linkage to the transmission needed adjusting, very simple fix. I had the engine in high revolution but the transmission wasn't fully engaged and the shaft was rotating very very slowly. So slow that you'll think the prop isnt opening. Open the engine compartment and watch your shaft when someone puts it into gear. You'll see what I mean. By adjusting the linkage so that there is more throw on the shift lever at the transmission, it will fully engage into gear as soon as you shift into forward and the shaft will spin quickly right away. The prop will open even at idle.
