I tried changing a 26P Bravo this weekend on my 26' Patriot.
I need to reduce my rpm some. The 26P revs at about 6000 rpm but the 28P droped the rpm down to 4800 rpm. What would cause such a drop in rpm. The only difference in props is that the 26 is a brushed finish and the 28 is a polished finish both props have been balanced. I would like to get my rpms to about 5500 if possible.

I am told the difference between a 26 and a 28 bravo 1 should be about 400 rpm in stock form. Sounds like something else mus be wrong or the prop(s) arn't what they seems. What speeds were you getting with the 26 and the 28? That will help narrow down which one might be the problem.

At 6000 rpm I get about 80 mph with the 26, at 4800 rpm which is all the engine will turn with the 28 i get about 75 mph. It is a 540 ci block with a 1050 dominator.

Assuming 1.50 ratio drive:
26p @ 6000 rpm at 80 mph is a slip ration of 18%
28p @ 4800 rpm at 75 mph is a slip ration of 12%

Could it be that the torque range of your motor just can't pull it?

Were you trimmed up, similiar tabs etc when running?

One of those sets of props have been altered. It should be about a 600 rpm difference. Hence, the 26p should be running 53-5400 from my experiences.

Agreed, the normal difference should be around 400 rpm.

One or both sets aren't standard spec.