Wrong Prop?

[89SeaRay220]

3 years ago I repowered my boat with a 5.0l fuel injected mercruiser. The boat yard kept the same propeller on the boat from my old engine, a 6 cyl merc. It boat ran wonderfully with the new propeller. I got a new prop this year, i brought the old one to a shop, and had them get me the same one (i'm not sure now, if they gave me the same prop)

With my old prop, i would reach about 5000 RPM and hit about 39 MPH. This season, i have not been able to get the boat past about 4400 RPM, and i cant get the boat to run any faster than 30 MPH.

Does it sound like they gave me the wrong prop?

Any help would be greatly appreciated!

 

[Shadowcruzr]

SOunds like the wrong one. Sounds like your about 3" over pitched.

 

[Sandy]

Yikes, what you posted is pretty confusing, but it does sound like the present prop is either 3" overpitched ....and/or has had some other characteristic(s) changed (i.e., dia., cup, rake, metal type....).

Didn't you record what your old and "new" props were/are? Were they scanned with before and after printouts that would include that info?
Any chance the present prop has experienced a flotsam or bottom stike, or there is a contributory engine or, throttle control/cable adjustment or filter problem?

 

[jtybt15]

Sounds like a michigan prop.