Prop advice for balance between plane and speed

[mercuryrising]

I recently bought an 01 Stingray 220sx with a 350mpi Mercruiser and a Bravo III drive. The prop is a double 3 blade 13.75" dia. 28 pitch.
It struggles to plane out with 500 lbs people/stuff but will do it in about 8 seconds. With 800-1000 lbs it won't plane out unless people shift into the cuddy cabin.

With 500 lbs. Wife and I and stuff, gps top speed is 48mph and rpms about 4800 WOT. It cruises nicely at 27- 30 MPH, at 3500-3800 rpms, depending on water conditions, wind, etc.

I would think this motor would perform better. I will be doing a compression check this weekend.
If compression is good, I will be changing props to be able to plane out with the added weight of a few more people but don't want to kill the top end or cruising ability.

I welcome some guidance on the right prop to go to.

 

[Scott Danforth]

Im surprised you have enough motor to swing 28 pitch props. I would drop down in pitch a bit for the holeshot

 

[tpenfield]

Try a 26P set . . . it sounds like the boat has been setup for the top end speed at the sacrifice of the hole shot.

 

[QBhoy]

I’d be surprised if the props were wrong at 28”. I’d look elsewhere. I know of a much heavier And wider maxum 2400 with same engine and drive. It turns 26” props to just about 50 mph when going well, at 5000 rpm. Yours should be sleeker and quicker. Should go better I’d think.

 

[mercuryrising]

Thank you for the advice. After compression test I found 150 on every cylinder except for 4 which was 120. However the cylinder 6 had water in it. Bummer. I just replace the riser gaskets O I'm afraid I may have either a bad valve or cracked manifold. I guess it could be a head gasket or cracked head but I have heard that is a rare problem. Prop replacement will be on hold until motor is 100%. I am new at this so welcome any tips.

 

[QBhoy]

Thank you for the advice. After compression test I found 150 on every cylinder except for 4 which was 120. However the cylinder 6 had water in it. Bummer. I just replace the riser gaskets O I'm afraid I may have either a bad valve or cracked manifold. I guess it could be a head gasket or cracked head but I have heard that is a rare problem. Prop replacement will be on hold until motor is 100%. I am new at this so welcome any tips.

Thought it might be something like this. Sounds like a sticking valve from having water in number 4 previously.
worst case you check the riser and exhausts are sealing again and take the rocker cover off and have a look at the valves on 4 as it turns over. Might be obvious