PERFORMANCE PROP APPLICATION

[JeffK]

I own a Bayliner MS1500 boat and am currently running a Suzuki DT85 outboard. I've purchased a new 3-blade 16-pitch Suzuki SS prop for my boat/motor combo over the 3-blade 15-pitch aluminum which it came with. I'm happy with this set up but, the motor will turn 5800+ RPM at WOT trimmed out. I would like more boat speed not RPM, so next I bought a new Michigan Rapture 3-blade SS 17-pitch thinking it would be the ticket when running the river or big lakes with light load...It killed the performance...The motor will only pull 5050 RPM and lost a full 5+ MPH at WOT. My thoughts are to bail on the Rapture and either go with a 4-blade 16-pitch Suzuki SS or try a different brand of 17-pitch 3-blade set up thats not so severely cupped. I'm not going to get much more power out of the motor as it's already set up with 2-stage Carbon fiber reeds, Main jets are spot on. Cylinder compression at current 172-175 PSI in all 3-cylinders. My thoughts with the 4-blade are to reduce some of the WOT slippage and the thinking with the 17-pitch 3-blade is stay away from the aggressive cupping to aquire some moderate slippage so I can pull 5400-5500RPM. Can you help me get more SPEED?

 

[JB]

Re: PERFORMANCE PROP APPLICATION

Hi, Jeff.<br /><br />No prop is going to add HP to your engine or change its rpm at peak hp.<br /><br />The 16" SS prop is optimizing your engine performance the way it is rigged. Putting the 3 blade 17" on it was like climbing a steep hill in overdrive; overworks the engine and slows the whole rig. A 4 blade 17" will be worse.<br /><br />I suggest that you look into how your engine is rigged, bottom condition on the boat and perhaps a stronger engine.<br /><br />DHadley may come along with some more specific suggestions.<br /><br />Good luck.

 

[JeffK]

Re: PERFORMANCE PROP APPLICATION

Thanks JB, I was looking at a 16 4-blade with out the rad cup or rake. I agree that the horsepower is not going to change with props. Thought the 16p 4-blade might reduce slippage a little over current 16p 3-blade to get a little more MPH and reduce full throttle RPM. JeffK