New Prop, slow MPH, higher RPM

[summerwind1991]

I have 5.7, marina told me a I needed a new prop so I had them put one on. It's Bravo II, however since, boat runs 4-5 MPH less, and at full throttle it gets scary close to max RPM.<br /><br />Is this a prop issue or could something else be causing full throttle topping out the RPM.

 

[walleyehed]

Re: New Prop, slow MPH, higher RPM

If the RPM is near Max, it has been set up properly.<br />It should run close to max RPM (or AT) at wide open throttle. sounds like they knew what they were doing to reprop for the proper RPM...This isn't a car, and for the best engine life and cruise economy, sounds like they got it right.

 

[imported_bjs]

Re: New Prop, slow MPH, higher RPM

put the old prop back on if dont feel you like the new is not ot your liking.

 

[summerwind1991]

Re: New Prop, slow MPH, higher RPM

IS there a way to find out if I have the correct prop, pitch diameter etc?<br /><br />My replacement prop for the 5.7 Bravo II is 16 1/2" x 23, a prop guy told me the diameter is incorrect, to small.

 

[gatorred]

Re: New Prop, slow MPH, higher RPM

what size is new prop, i see your from lake geneva are you in new york try here www.myspace.com/boatstuff my webpage if contact other the here

 

[b.gagnon]

Re: New Prop, slow MPH, higher RPM

Sounds like the new prop is the correct one!<br />Truth hurts!

 

[WillyBWright]

Re: New Prop, slow MPH, higher RPM

A Bravo II on a smallblock? Man, that's like putting a Chevette motor in front of a Semi transmission. <br /><br />That thing must have close to a 3:1 ratio to twist a 23. Are you certain of those nubers?

 

[summerwind1991]

Re: New Prop, slow MPH, higher RPM

The ratio is 2.2/1 210 horse with a 350 CID GM Block.

 

[Bondo]

Re: New Prop, slow MPH, higher RPM

and at full throttle it gets scary close to max RPM.

So,..... What,.. Exactly is the #,..????<br /><br />What's the WOT Range of your powerplant,..???<br /><br />Scary Close to the Max,.... Is where it's Supposed to Run,... At WOT.......<br />

My replacement prop for the 5.7 Bravo II is 16 1/2" x 23,

What are the #s for the Old Prop,..???<br />What Size is it,..???<br />What RPMs did it achieve,..??? <br />

i see your from lake geneva are you in new york

gatorred,.......<br />Geneva Lake is in New York,.. 1 of the Finger Lakes.......<br /><br />Lake Geneva is in Wisconsin...........

 

[Texasmark]

Re: New Prop, slow MPH, higher RPM

Kenny said it right (as usual). Even though you are going slower, you (they) have set up your engine to run where the designers wanted it to run.....at the top of the operating rpm range with your normal load at WOT. <br /><br />Any thing less and you are lugging it and it will wear out prematurely or cause you other problems like high fuel consumption and possibley carboning up....even though it is a V8 auto type 4 cycle engine.<br /><br />Guess you got spoiled with the faster speed. Don't blame you. Happened to me on 2 boats but I knew I had to prop down to avoid damage.....but it was fun while it lasted.<br /><br />Mark

 

[gatorred]

Re: New Prop, slow MPH, higher RPM

thanks bondo just tring to help if close to him