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7.4 mpi 1998 ?

J

jeffnoank

Member
I just purchased 26' proline cuddy cabin, 9 ' 2" beam, about 7000lbs. The engine is a 310hp the boat came with a Bravo 3 drive, drive had issue. My marina suggested I put a Bravo 1 drive on, simple and should be faster, it also came with a 19" pitch aluminmu prop.

After a few seatrial we are seeing top end about 4500 rpms, 27 knots and on plnae cruies at 3600 rpms about 19knots. Everything I have learned about this engine and motor is I should be seeing a much much higher speed at cruise and top end.

My marina wants to try a SS 17" marage prop, they think this will help a lot.

What do the hands on folks on this forum think ? Should I be seeing a greater speed with this config ? Should the SS prop help ? thx jeff
 
That's a lot of torque and a heavy load for an aluminum prop. I think SS would be better and I like the plan of going with a 17". That said, a heavy, and beamy boat like that would be better suited to a slower-turning/larger blade area Bravo 3.
 
Well first off,

having a bravo 3 duo prop is a better drive than a bravo 1,for starters the bravo 3 is a duo prop where bravo 1 is a single prop.duo props always plane a boat faster and is way more efficient in the water hands down...
second off,single props have more cavitation(slippage) in the water than
a duo prop therefore it really couldnt be faster.either way the bravo drives are good drives regardless of single/duo prop option.If i were you id keep the duo props for fuel savings and efficiency.Good Luck
 
You may never get more out of it. What you will do is turn the prop faster with less pitch put you won;t get more top end.

You tried trimming it. To hit the sweet spot.

Maybe what i posted is not what you want to hear but whatever you do don't go over recommended wot. If it is 4200-4600 wot then you cannot go over or you will blow the motor.

To me it seems you hit the limit. Look on the motor what does it say for wot ?
 
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