The hub on the prop is prob. "spun". Take the prop off and look between the inner splined brass hub, and the outer prop housing. You should see a rubber bushing between the two. The rubber is a coushion but will start to slip over time or due to abuse.The damage should be obvious (rubber shreds or globs comming out). If not, mark the inner hub and the outer prop housing, run the motor in gear, fast enough so that you notice the slipping. Then look at the marks and see if they are still lined up. The inner hub should not move at all, compared to the rest of the prop.
BA
October 2007