3081 or 3087 G23 with H6 stock ballast

[greggmck]

I have been reading about how direct injection ECUs are programmed. It appears the H6Di ECU is programmed for maximum fuel and emissions efficiency with the stock 17x17 prop. The ECU will target a lean fuel / air ratio to produce the lowest emissions and fuel consumption. With the increased load of the 17 1/2 x 17 1/2 the ECU richened the mixture to increase the power output. This explains the roughly 10% increase in fuel consumption while operating at lower RPM. The results could be very different for the 550 HP supercharged engine.

[ST3]

I have been reading about how direct injection ECUs are programmed. It appears the H6Di ECU is programmed for maximum fuel and emissions efficiency with the stock 17x17 prop. The ECU will target a lean fuel / air ratio to produce the lowest emissions and fuel consumption. With the increased load of the 17 1/2 x 17 1/2 the ECU enrichened the mixture to increase the power output. This explains the roughly 10% increase in fuel consumption while operating at lower RPM. The results could be very different for the 550 HP supercharged engine.

Really appreciate all of the time / effort you put in here. Have you spoken to Nautique or PCM to see if they have any guidance toward achieving your goals of noise and fuel reduction? I am really surprised that you didn’t get some fuel savings...

[greggmck]

Really appreciate all of the time / effort you put in here. Have you spoken to Nautique or PCM to see if they have any guidance toward achieving your goals of noise and fuel reduction? I am really surprised that you didn’t get some fuel savings...

Not yet. I am still waiting to speak with the guys at ACME first to see what other props they might recommend.

They are on an extended Memorial Day vacation.

They have a 30 day exchange program and I will take advantage of it. Worse case is I go back to my 17x17.

[RDT-G23]

I had my 3087 installed and only have about an hour on it, so I'll give a more thorough review after the week of July 4-when I will put plenty of all purpose time on it. Reading greggmck's posts, it is clear that he and his family are as serious about surfing as anybody on the board; to maximize that specific experience for them, is logical. I, on the other hand, use my boat for just about everything. I want a top notch surf wave, but also pull tubes, wake boarders, and often simply cruise up the lake in the evenings with no ballast or people pulling. Other than surfing/wake boarding, I find the boat to be a bit of a "Screaming Meemee" at any kind of speed cruising. (These are, after all, purpose built "tractors" on the water.) I'm not trying to make the boat a stern drive, but think the 3087 will knock down the RPMs slightly to allow for a more rounded/quieter experience. Finally, I never surf with a group of 14-200lb bodies in the boat, so getting to surfing or wake boarding speed is no problem in any event.

[GMLIII]

I had my 3087 installed and only have about an hour on it, so I'll give a more thorough review after the week of July 4-when I will put plenty of all purpose time on it. Reading greggmck's posts, it is clear that he and his family are as serious about surfing as anybody on the board; to maximize that specific experience for them, is logical. I, on the other hand, use my boat for just about everything. I want a top notch surf wave, but also pull tubes, wake boarders, and often simply cruise up the lake in the evenings with no ballast or people pulling. Other than surfing/wake boarding, I find the boat to be a bit of a "Screaming Meemee" at any kind of speed cruising. (These are, after all, purpose built "tractors" on the water.) I'm not trying to make the boat a stern drive, but think the 3087 will knock down the RPMs slightly to allow for a more rounded/quieter experience. Finally, I never surf with a group of 14-200lb bodies in the boat, so getting to surfing or wake boarding speed is no problem in any event.

Looking forward to your report back to the forum

[ironj32]

I'm doing some testing with a few props and my XR 550. I seems that the H6 doesn't necessarily improve fuel economy when spinning lower RPMs, rather it increased it. Does anyone have insight into the 550?

I'm trying to debate if I want to ride at speed with 300 less RPM, or shave 2-3 seconds off of my time to speed. The prop that is quicker out of the hole actually runs the same RPMs as the stock prop (but it's about 6 seconds faster out of the hole than stock).

[greggmck]

Looking forward to your report back to the forum

I think you will find the #3087 17 1/2 x 17 1/2 to be the perfect prop for your needs as described. It does reduce the engine noise and RPM by about 250 - 300 for similar speed operations compared to the stock ACME #2651 17 x 17. In my case the surfing load caused the ECU to run the fuel mixture more rich to generate increased power at lower RPM. I have spoken to ACME and they are sending me a 17 1/2 x 17 prop with the same cup. I am hoping this will allow the engine to run more lean during full load surfing and provide a good compromise of fuel burn and reduced RPM. I should receive the prop tomorrow and get some time on it this weekend.

[RDT-G23]

I never did come back and report on the ACME 3087. In short, I love it. It drops RPMs 250-300. Surfing at 11.2 MPH, I'm turning 2900-3000 RPMs. Again, I usually surf with no more than 6 adults in the boat, and use full factory ballast. I also pull tubes, occasionally pull wake boarders, cruise up the lake, etc. In other words, I'm not a competitive surfer, or boarder. This move has made the boat more civil. I have no clue what the fuel usage trend is since the change, and really don't care; I’m pleased.

[TimmyH79]

greggmck - ever get that new 17.5 x 17 prop in from Acme and any update? Looking to pull the trigger on a new prop for my H6 and 3087 seems consensus choice but curious about your results, if the rpm reduction is same/similar than sticking with stock pitch could be attractive

[greggmck]

greggmck - ever get that new 17.5 x 17 prop in from Acme and any update? Looking to pull the trigger on a new prop for my H6 and 3087 seems consensus choice but curious about your results, if the rpm reduction is same/similar than sticking with stock pitch could be attractive

On the last day of testing the 17.5" x 17.5" prop the shaft failed and the prop fell into 60 feet of water. I never had a chance to test the 17.5" x 17. But I believe it would have been ideal for my needs ( best fuel efficiency and low engine noise). After the shock of having the shaft fail, I didn't want to mess around with new props. Since then I have learned much about shaft failures that occurred on the 2018 G23s. These particular failures were due to the key way being cut too long.

To identify the defective shafts on a 2018 G look at the shaft on the forward side of your prop hub. Rotate the prop to see the entire shaft. The affected shafts have the key way protruding about 1/4" beyond the prop hub. I would be hesitant to increase prop diameter with these shafts. Otherwise in my opinion the 17.5" x 17" prop would be ideal for an H6Di G23.

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[SoCal G-Man]

On the last day of testing the 17.5" x 17.5" prop the shaft failed and the prop fell into 60 feet of water. I never had a chance to test the 17.5" x 17. But I believe it would have been ideal for my needs ( best fuel efficiency and low engine noise). After the shock of having the shaft fail, I didn't want to mess around with new props. Since then I have learned much about shaft failures that occurred on the 2018 G23s. These particular failures were due to the key way being cut too long.

To identify the defective shafts on a 2018 G look at the shaft on the forward side of your prop hub. Rotate the prop to see the entire shaft. The affected shafts have the key way protruding about 1/4" beyond the prop hub. I would be hesitant to increase prop diameter with these shafts. Otherwise in my opinion the 17.5" x 17" prop would be ideal for an H6Di G23.

Sent from my SM-G965U using Tapatalk

Good info on the shafts. I had one break, but I should probably look at the replacement to make sure it is not the same design. Thank you for the info!

[Tallredrider]

Gregg very well may be right, but it is a theory at this point, and it is obvious that even the guys at Nautique have not solved the problem. If the dealer will replace it for free, I would do it, but I don't think I personally would pay for it without more reassurrance that virtually none of the shorter key shafts ever break.

[TimmyH79]

Gregg, thanks for the quick feedback - I have also been seeing the threads on shaft breakage and it was one of the reasons was looking to keep as close to stock as possible while still hoping to achieve some noise (primary) and gph (secondary) gains. Perhaps I'll give the 17.5" a try - looks like Acme has it labeled as the 3085

I will have a chance to take a look at the shaft tomorrow when I drop off my 210 and will investigate the keyway - appreciate the info

https://acmemarine.com/products/acme-propeller-3085

[TimmyH79]

Checked out my boat today and based on the attached picture suppose I would at least be in the lower risk category of shaft shear but feedback welcome

the keyway appears to end right at aft end of strut and definitely does not extends to forward side

apoogies - pic seems to be upside down and don’t know how to rotate

[Tallredrider]

greggmck, do you mean the keyway, or the key itself? My key is placed just inside the hub, but the carved keyway goes up quite a ways beyond.

My key ends at the prop hub, but the shaft has a groove that extends quite a long ways.

It almost looks like the key is not squarely placed into the keyway...I don't dare mess with it, since it has served me well for 337 hours now.