Newbie prop replacement

[markallen]

Hi Gang,

Recently retired and decided to take up boating. After reading some of the technical info on props, maybe brain surgery would have been an easier endeavor.

Took my boat out yesterday and had a terrible time just trying to get it up on plane. This is only the second time I've had it in the water. The first resulted in an oil leak after 20 minutes so I never really got much exposure to it.

The boat is a 21 foot 1992 Trophy 2159.

1) Performance issue you are trying to correct:
Boat had a very difficult time getting up on plane

2) Current prop manufacturer, model, aluminum or stainless as a minimum:
Prop is black painted aluminum. It is stamped: 48 832828A45 17P

3) Current prop diameter and pitch (required).
I'm guessing the "17P" stamped on the prop is pitch. Not sure about diameter.

4) Wide open throttle RPM and speed with an average load (very helpful)
I had a full tank of fuel (86 gallons), three average adults and when I was able to achieve plane, the engine ran at about 4700RPM The vast majority of the time I had the throttle wide open and was not at plane and running about 3300RPM

5) Engine/drive make, model, year, and HP
Engine: 1998 Mercruiser 4.3LH 262 ci
Drive: 1992 Alpha One - Gen 2

6) Boat make model, year, length and weight
1992 Bayliner Trophy 2159 3450lbs

The existing prop does look a little beat up bit not substancially damaged. Since I know the engine has been changed out I have no idea if it is the proper prop for the boat.

My objectives for the boat is something to cruise around on and able to maneuver easily. Going as fast as possible is not a top concern. Being able to get up to (or is that "on") plane easily is more important.

Thanks in advance for any help. Everyone here has been so helpful, I greatly appreciate it.

Cheers,

Mark

 

[Sea Rider]

Firstly, engine must be running 100% strong, secondly, test current installed prop, could be on its way to become spun, it's not working correctly. Will need to perform a hub slip test. If found in good shape, could be over propped, if so, will need to drop down some pitches in order for engine to rev upwards towards max wot rpm range factory stated and plane the combo much faster as usually loaded. Report your findings...

Happy Boating

 

[markallen]

Thanks. I'll check those items and report back.

 

[Scott06]

You're already achieving WOT for that engine at 4700 rpm. A couple of questions and comments

is the hull clean?
Has it taken on water under the floor making it heavier?
As above ensure the engine is in a good state of tune ignition fuel delivery etc and prop hub isn't spinning.
Is current prop in good condition?

whats the drive ratio? I assume a 1.82 or so? thats a fair amount of boat weight for that engine - 2 bbl or 4 bbl carb?

If lower planing rpm is your goal would suggest after you rule out above items looking at 4 blade props as they will help get up and on a plane better vs 3 blade. Assuming other issues are ruled out would think a 16" Michigan vortex 4 blade would be a realatuvely cheap what to trial.