2003 Nissan 9.8 2 stroke Wheezing

A few fishing trips ago I noticed a lack in speed from about 12mph to 6ish mph. Also, there was a faint sounding wheeze I thought I heard coming out of the middle/lower unit. I also put a mark on the prop and when I last hauled the boat I learned my prop hub was spun. Previously the motor ran at around 4400RPM's so I bought a new prop that was pitched 1 click down, (8 pitch to 7). I took her out last night with the new prop and she ran at 5300 RPM's WOT and ran a little over 12mph. When juicing her up out of the hole, that wheezing sound was more prominent but when she gets on plane the wheeze would subside. When I got her home I changed the lower unit oil. It didn't look great.



Would any of you guys suggest something else to check? I'm assuming the higher RPM's under a load is causing the wheeze. The boat is 14' Sea Nymph with 2 guys and fishing gear.

Thanks!

I'm looking to run her tonight again. Any advice on diagnosing the whining noise? I'm thinking about doing another lower unit oil change in the parking lot as soon as I pull her when it's still warm.