More info as requested.
1. Prop and hull are clean
2. No oil leak
3. No blue smoke
4. Black Smoke and smell bad
5 Underload, engine will not rev high
Unless the mechanic is sufficiently "confident" that he'd be willing to reimburse the cost of a short haul if it turns out the Max-Prop is fine, I'd seek a second opinion...That was my original request to test the engine first. Perhaps do the compression test and test the injectors. I agree that tt is far cheaper than haul out the boat. But the mechanic was so confident it was MaxProp problems.
It's hard to believe the MaxProp blades are not operating synchronously, given the way it is constructed (bulletproof gearing). If there was mechanical interference with the prop, there might be differences among the blades (e.g., bends, tears). I had snagged a cinder block about 10 years ago with my MaxProp and all three blades were dog-eared and torn. Sent it to PYI to have it remanufactured. Even with this damage, I was able to motor to a marina.Gee whiz, if it's the original setup, and it used to run fine, what kind of Maxprop issues does he think it is? If one of the blades isn't feathering completely I'd expect you'd sure know it via hellacious vibrations when in gear. Maybe send a diver down first for a look see? Unless there's other stuff you've been wanting to do with the boat out of the water...