Prop slipping?
 

2006 Sunsation 288
525 EFI
bravo XR drive
ITS transom assembly
bravo 1 15.25 28 pitch brand new

Hello, just bought boat. Was told boat went 80mph. First time out boat maxed at 67 with 1/4 tank and 1 person at 5100rpm. As soon as the boat comes up on plane the rpm’s come up at least 1500 like it breaks loose. Was told prop was worn out. Ordered new prop exact replacement. Boat now does 72 with a full tank and 3 people. But the prop still slips a lot as soon as the boats gets on plane. Any thoughts on what’s causing this? It also cruises at 40mph at 3500rpm. Does that sound normal? Thanks

It is a bravo 1 FS 28 prop and I have all the plugs installed. The original was a reg bravo 1.

Yeah, you're slipping terribly...something like 35% at 40 mph and 21% at 72. This setup have a prop hub or is it solid? If hubbed, did you replace it when you did the new prop?

80 at 5100 ia only 11% slip, which would be very reasonable. Objective evidence indicates something changed from old owner's 80 mph boat to your 72 mph boat. Look to see what that could be. Obviously driver is one factor. Weight and balance could be another. Gotta ask if you are trimming the outdrive correctly?

it is a solid hub. I bought a new solid hub with the new prop but i reused the old one and had a shop inspect it and they told me it was fine. Kept a the new one as a spare.

I agree and I’m trying to figure out what. Maybe it’s not the same prop and he kept the good prop and gave me a **** one he had laying around. I didn’t mind buying a new one just to have a baseline to give accurate rpm information to a prop shop. But my main goal is to determine if it’s a prop issue or something else slipping. No rubber smell from engine and hub on back of motor was done last year.

im new to boating but I have an experienced friend who gave me some good advice and I also had him take it out to rule out operator error and the performance did not change. He told me something is wrong and it’s def slipping.

I'm not convinced that boat will run 80. Did you ride in it with the previous owner? That aside, maybe you should try a Bravo 1 30p or a 5 blade 30p. Bblades has a prop testing program.

I just did a quick search 525efi Sunsation 288 speed and got lots of prop and speed threads. Looks like 80 is very high end of possibilities but many ran not far from there. Many 76-78’s.

A 26/27 Daytona runs low 80s with that power. I would think about 74-5 mph is about right for this boat. I would still try a different prop.