offshorexcursion

iTrader: (5)

My good buddy has a really nice 2001 280 silencer with a fresh merc 502mpi spinning a 24 b1 about 5100 rpm at 60mph. What's wrong?

I plan on driving the boat tomorrow anything I should know to help him out? How far does These boats like to be trimmed up? Tabs? I'm pretty good at getting a feel for what a boat wants but also am not afraid to learn from the power of OSO.

Overall I am really impressed with his boat it just needs to go the speeds we thought it should..

Post your speed, prop, rpm, and propshaft height please.

Thanks!

TPro587

I also have a good friend that has a 2000 280 silencer with a 502mpi. He is spinning a 4 blade, 26 pitch b1. In perfect conditions with 2 people on board, he will run 67mph with some trim. RPMs at WOT are around 5000-5100. I don't know the exact propshaft high but I know it was never raised, so probably the same height as your friends boat. I hope this help a little bit.

offshorexcursion

iTrader: (5)

From other threads a labbed 26 Bravo 4 Blade sounds like its worth a try. Any other ideas or options on what could be wrong besides prop?

TPro587

I am far from an expert, that is for sure! But was the engine put on a dyno after it was freshened up?

verbi69

A Bravo 26 pitch will kill your top rpm as your already at 5100. These boats do not like a whole lot of trim. The boat hull will feel like it frees up and feel faster when in fact a gps will show it slowing down in mph.

My 03 with a stock 496HO would run 64-65 mph for comparison. With 565HP it ran 73ish....

murf

I have a 2000 Silencer. Stock 502 MPI I am running a 24 b1. At 5100 RPM's I am seeing at least 65 MPH. The Best I've seen was 67 MPH.
Does your friend have a drive spacer?

AJ POWERPLAY

iTrader: (1)

Mid-60's with that power is normal, get your girly hands on the throttle and push forward!!

ericwinters

67 with a 26" is actually right on the money for that boat (I had 74 MPH-GPS at 5400 RPM with the same prop/same boat with a 525 EFI-17% slipage with a single person in it, 28" regular Bravo 1, same speed at 5100 RPM, too much prop, currently right at 80 MPH with the 28" Cutting Edge Laser Labbed prop, take's off a little slow at 1/2 or full throttle but once on plane, it takes off like a Corvette), it's the best prop by far and it's not even close, their laser labbed props will get you the maximum RPM's and top end, they look like a they were sharpened with a sharp knife sharpener on the forward side, you can practically cut yourself on that edge they are that sharp, Mercury Racing has nothing like that. For the ultimate blast, there is a 575 SCi (which is all an XR drive will take away) on Ebay right now for $16,000 and it will fit in that boat and it should run 30" Labbed CE Prop 80-85 MPH maybe 90 MPH after Tyler Crockett tunes it, he's Mr. Wizard with Mercury Racing Tuning.

ericwinters

24 pitch should around about 67 MPH at 5150 RPM without trim, I started off with a 525 EFI with a 26 pitch and it ran 70 MPH at 5400 with some trim, so a 26 pitch might be a little steep for that powerplant.

ericwinters

You're right not enough power for the 26", you will need a 500 EFI or a 525 EFI to run that prop on that boat (525 EFI ran 70 MPH at 5400 RPM with some trim), possibly a 26" hydromotive may run on that powerplant, but that prop will cost you some money to get one.