prop question

[Rob454]

Ok guys<br />I have a 89 Bayliner 19 foot Capri open bow. it had a 5 liter v8 and OMC outdrive. I jsut had the motor replaced and it runs great. The only thing is the boat only revs to 36-3700 RPM. but it was sort of rough out that day. It has great pick up off the bottom. Now I looked and i saw the last owner had a 4 blade prob and there is a 3 blade prop in a storage bin. The 3 blade prop looks like it got dragged up a launch ramp or hit something so its unuseable. <br />Now I had jet skis and When you switched to a different prop you could loose as much as 500RPM from the top. Anyway I know a a bunch about jet ski props and wont bore you. Im thinking I should go back to my stock 3 blade prop. I dotn plan on towing skiers and If I do the prop is a snap to change. What is the stock prop for that bayliner?<br /><br />Thanx<br />Rob

 

[SpinnerBait_Nut]

Re: prop question

Hey Rob, I will get this to the prop forum, but will leave it open here also.

 

[Purduebarry]

Re: prop question

Rob,

I have an 1988 version of the exact same configuration, 5.0L, OMC. My manual says RPM's should be 4200 to 4600 at WOT. That 4 blade must have a really high pitch? The three was probalby original. My set-up has a 14.5 x 19. This is the OEM configuration.

Check here on i-boats they have a selection tool and also the Michigan Wheel web site has a great selection tool.

You MUST be wihtin your suggested RPM range at WOT. That is the law, anything else is a slow death for the engine, drive or both. Over prop and the engine will labor, under prop and it will over rev. Increase pitch = lower RPM and decrease pitch = higher. If everything is correct, tach, speedo, tune up of engine etc. you should be at 4400 RPM's at WOT.

With a light load on smooth water you'll get around 45 MPH, give or take 5 MPH depending on conditions. A higher pitch prop (assuming what you have now) may get you faster top end but your killing the motor and drive. You want efficiency right now you don't have it. Also this is assuming your not carrying around a ton of water logged foam. That's another subject I'm in the midst of correcting.