RPM dilemma
 

Have a 97 252 SS 454 MPI LX Bravo III 1:81 w/ 28p props.. motor was just replaced with a remanufactured long block. According to diagnostic computer everything is set up just the way it should be, but can only get about 4100 RPM's @WOT. Do not know what top speed should be,but know I should be able to get 4600 RPM's at WOT. Anyone know someone good around Pittsburgh Pa. that could correct this situation?

Are you sure the long block is identical? Did you happen to maybe go from a MAG to a non-MAG motor with lower compression?

I'm not 100% absolutely certain. When I purchased the long block , they asked for my serial number and said that was all he needed to match motors. They told me it should have 340 hp instead of the original 330 hp. The crank was out when I bought the boat so , I don't know how it ran prior to rebuild. Have you dealt with Low RPM issue before?

Mike

How much fuel / gear / people are on the boat? If it's heavily loaded that could make a difference in the max RPM. Also are you sure that the 28p props are the correct pitch for that hull with a 330?

When I pulled it out of the water last week I was alone, >20 gal. of fuel, some towels and life jackets. 4100 RPM tops !!! I'm assuming that the 28p props were original, but I have not contacted Formula as of yet to verify. My motor guy says he is baffled. Computer diagnostics are all good and all linkages hooked up properly. Was thinking about a different motor guy. Recommendations ?

I would certainly give formula a call or shoot them an email to find out what the stock props were. Who knows if the previous owner damaged a blade and replaced the set with a used one of the wrong pitch?

I'm not a bravo 3 expert, but they must run a lower gear ratio. A 28 on a B1 would be WAY over propped for that boat.

It sure seems to me that you may have a prop issue. I would verify that first since it could be the cheap easy fix.

I will pm you a contact at formula...

Thanks Artie, will let you know what I find out!!!!!

If that boat is over propped and it was run like that it could explain the engine problems.

I have a 38 Fountain EC with twins, 1.81:1 B3 runing 25" pitch bravo III XR props. four blades on the leading prop, 3 blades on the trailing prop. My buddy has a 25' Monteray with B3 2.2:1 running 25" B3 props. I would try props first, Formula will tell you what it should have.

Thanks guys!!! Scott @ Formula says that the boat came with 28p props. My guess is something else is up . Know any reputable motor guys?