I have little to no experience with outboard motors. This 18 hp fastwin I got for my inflatable seems like a basket case. I dropped the lower unit to replace the impeller and got real curious about the amount of play I found in the prop. I literally cannot get the screws to budge holding to case together, so I can't readily take a peak inside. The prop will rotate, in either direction and in neutral forward or reverse, one prop blade as much as 90 degrees, or one blade from 12 o'clock to 3 o'clock position before engaging anything. My gut is saying that's too much play, way too much. Any thoughts?