New prop - but less RPMs - SuzukiDF40

[Islandman54]

I just replaced my prop on Suzuki DF40, on a 24 ft pontoon boat. The old prop would get about 5800 RPMs, but with the new prop only about 5000. Should I be concerned? Old prop was 11 5/8 X 12; new one 11.6 X 12.

 

[ahicks]

If pulling anything, like one of the grand kids on a tube, you'd probably be loosing some performance with the 5k prop. Maybe enough to make you want to do something about it. As long as you're OK with the performance you're getting with the new prop, you should be fine.

 

[Sea Rider]

Were both props Susy OEM ones with just diam differences ? What's the min-max wot rpm range factory stated for that engine ?

Happy Boating

 

[Islandman54]

WOT on this motor (2005 DF40) should be about 5800 rpms. Now prop is a Solas. The old prop (not sure of OEM) was turning 5800.
thx

 

[Scott06]

Would think the new prop has more cup and blade area vs old one which would give more grip on the water and lower rpms and slip. Is it possible old prop had been worked or repitched? You may see hand stamping on the prop denoting a repair job.

 

[Sea Rider]

Achieving way less or more wot rpm usually results when going from factory delivered OEM props to other brand props. If with new Solas prop only achieved just 5 K wot revs as loaded provided that engine runs strong and tach its doing his homework right need to drop some pitch sizes, say to a 10 pitch while maintaining same brand model, test and check if engine has increased its wot rpm range towards max wot range. Or re pitch new prop at a prop shop from 12 to a 10 pitch one and test.

It's much easier to dial top prop performance while maintaining same prop brand playing with just pitches on second try than going per other prop brands as in your case. Seems will need a third prop try if a 10 pitch doesn't work as expected.

IF OEM prop was revving fully to max 5.8 K wot revs, why needed a new Solas prop with same pitch for ?

Happy Boating