esfishdoc
Well-known member
Prop Stuff….
I now have the Stilleto 14.25 X 17 three blade stainless steel prop purchased from Overtons’s for 309.95.
As you know….. Most of us with the 2520XL and F225 have been using the factory prop which was a 14.5 X 19. On my boat WOT was never over 5300 rpm.
The general consensus was that the engine should max out around 56 to 6000 depending on the source. Having a wide open throttle achieving only 5300 suggests that at some points in the power band the engine would be lugging and that this is not a good thing.
With the old prop I was happy with the performance and would not have considered changing if it weren’t for the internet and the ability to learn and compare data.
Armed with the notion that better performance was possible and eliminating the potentially harmful “lugging” I went ahead and got the above mentioned prop.
Several days ago I was out with an unusually heavy load and could not properly compare performance (in general I was not happy with the numbers I was seeing).
Today I went out with my wife, about 130 gallons of liquid gold, and about 20 gallons in the live well and another 12 or so in the fresh water washdown unit.
With the older prop I never took down accurate numbers throughout the range but on calm water at 4400 rpm a speed of 27 to 28 and a fuel consumption of 11 to 12 gph seemed to be the sweat spot.
Today with the new prop…. About a 10 mph wind with less than a foot chop (will have to compare later with the slick cam….) trim tabs were up for all these numbers and the engine trimmed for best ride… about a 2.5 on the Yamaha meter FWTW.
Rpm – speed in mph from gps – gallons per hour 87 octane
4600 – 24.5 – 10.7
4600 – 23.6 – 10.8
4700 – 25.5 – 11
4700 – 26.6 – 11
4800 – 27.4 – 11.4
4800 – 28.2 – 11.3
4900 – 28.0 – 11.3
5800 – 34.0 – 16.6
5800 is WOT although I did see it flick up to 5900 briefly.
The numbers do not tell the complete story.
There is a big difference in the ability to get up on plane…. Don’t ask me for times ….. I don’t know them but I can feel the way the engine winds up and the boat feels. It gets up to speed faster and up on plane quicker.... not important to me but might come in handy some day.
It will be interesting to see how things go in the future on glassy water and out on the ocean……… I recall a day last year on the ocean when I was coming in with a following sea……. In the inlet when you start to have that sensation that the boat is getting sucked into the wave behind you….. giving it the throttle and little to no increase in the rpm because…. Well I guess the engine was lugging and maxed out. I think this prop will perform differently.
When using the Navman in the MPG mode I never saw better than 2.3….. I did not write down all the data in MPG so I can’t comment further on that.
All in all I’m happy. I’m not convinced completely which will cause the engine to wear out sooner….. more rpm’s over the lifetime versus lugging….. seems like most say lugging. As long as this engine keeps working until Yamaha comes out with a 300 hp four stroke I’ll be happy.
Richard
I now have the Stilleto 14.25 X 17 three blade stainless steel prop purchased from Overtons’s for 309.95.
As you know….. Most of us with the 2520XL and F225 have been using the factory prop which was a 14.5 X 19. On my boat WOT was never over 5300 rpm.
The general consensus was that the engine should max out around 56 to 6000 depending on the source. Having a wide open throttle achieving only 5300 suggests that at some points in the power band the engine would be lugging and that this is not a good thing.
With the old prop I was happy with the performance and would not have considered changing if it weren’t for the internet and the ability to learn and compare data.
Armed with the notion that better performance was possible and eliminating the potentially harmful “lugging” I went ahead and got the above mentioned prop.
Several days ago I was out with an unusually heavy load and could not properly compare performance (in general I was not happy with the numbers I was seeing).
Today I went out with my wife, about 130 gallons of liquid gold, and about 20 gallons in the live well and another 12 or so in the fresh water washdown unit.
With the older prop I never took down accurate numbers throughout the range but on calm water at 4400 rpm a speed of 27 to 28 and a fuel consumption of 11 to 12 gph seemed to be the sweat spot.
Today with the new prop…. About a 10 mph wind with less than a foot chop (will have to compare later with the slick cam….) trim tabs were up for all these numbers and the engine trimmed for best ride… about a 2.5 on the Yamaha meter FWTW.
Rpm – speed in mph from gps – gallons per hour 87 octane
4600 – 24.5 – 10.7
4600 – 23.6 – 10.8
4700 – 25.5 – 11
4700 – 26.6 – 11
4800 – 27.4 – 11.4
4800 – 28.2 – 11.3
4900 – 28.0 – 11.3
5800 – 34.0 – 16.6
5800 is WOT although I did see it flick up to 5900 briefly.
The numbers do not tell the complete story.
There is a big difference in the ability to get up on plane…. Don’t ask me for times ….. I don’t know them but I can feel the way the engine winds up and the boat feels. It gets up to speed faster and up on plane quicker.... not important to me but might come in handy some day.
It will be interesting to see how things go in the future on glassy water and out on the ocean……… I recall a day last year on the ocean when I was coming in with a following sea……. In the inlet when you start to have that sensation that the boat is getting sucked into the wave behind you….. giving it the throttle and little to no increase in the rpm because…. Well I guess the engine was lugging and maxed out. I think this prop will perform differently.
When using the Navman in the MPG mode I never saw better than 2.3….. I did not write down all the data in MPG so I can’t comment further on that.
All in all I’m happy. I’m not convinced completely which will cause the engine to wear out sooner….. more rpm’s over the lifetime versus lugging….. seems like most say lugging. As long as this engine keeps working until Yamaha comes out with a 300 hp four stroke I’ll be happy.
Richard