2011 Bayliner 285 with a new engine and prop!

[fr13sorch1ps]

my friend is a doctor (super busy working at a hospital here in the US), just went through a whole thing with his 2011 Bayliner 285.

He recently swapped out the old Mercruiser MPI 5 liter V8 engine for a newer Mercruiser 4.5 liter V6 on the Alpha drive.

Apparently, figuring out the best prop was a real headache. It took him a while, but he finally landed on the Mercruiser 21" prop.

His technician was actually pushing for a 17", but my friend said they were only hitting 10 knots at 4000 rpm with that, so they figured bigger was better.
Just thought I'd share his experience since it was quite a project for him!

 

[DeckDrifter]

That's a cool project your buddy did! Getting the right prop after an engine change can be tough. It makes sense he went from a 17″ to a 21″ if he was only hitting 10 knots at 4000 RPM, sounds like the prop was way too small. I'm glad he figured it out.

Did he check his RPMs at wide open throttle with the 21″ prop? Just wondering if it's where it should be for that 4.5L engine.

 

[baymagiic]

my friend is a doctor (super busy working at a hospital here in the US), just went through a whole thing with his 2011 Bayliner 285.

He recently swapped out the old Mercruiser MPI 5 liter V8 engine for a newer Mercruiser 4.5 liter V6 on the Alpha drive.

Apparently, figuring out the best prop was a real headache. It took him a while, but he finally landed on the Mercruiser 21" prop.

His technician was actually pushing for a 17", but my friend said they were only hitting 10 knots at 4000 rpm with that, so they figured bigger was better.
Just thought I'd share his experience since it was quite a project for him!

Interesting swap! Going from the 5.0L V8 to the V6, especially with the same Alpha drive, would definitely make prop selection a puzzle. Glad to hear the 21" prop got him where he needed to be! I'm curious if noticed any significant changes in fuel economy or handling with the new setup?

 

[Thamuz]

my friend is a doctor (super busy working at a hospital here in the US), just went through a whole thing with his 2011 Bayliner 285.

He recently swapped out the old Mercruiser MPI 5 liter V8 engine for a newer Mercruiser 4.5 liter V6 on the Alpha drive.

Apparently, figuring out the best prop was a real headache. It took him a while, but he finally landed on the Mercruiser 21" prop.

His technician was actually pushing for a 17", but my friend said they were only hitting 10 knots at 4000 rpm with that, so they figured bigger was better.
Just thought I'd share his experience since it was quite a project for him!

Damn happy for him for sticking with it and seeing his hardwork pay off. TBH props can make or break the setup, so glad the 21" got him back on track.

 

[Knotty_Buoy.260#]

That makes sense, switching from a V8 to a V6 definitely alters the torque curve, which can complicate propeller sizing. That 21" pitch probably helped bring back some top-end speed and efficiency. It seems like he made a smart choice.