2015 ASR won't go above 3100 RPMS when loaded

[ynot]

Hi everyone!

I have a 2015 ASR with the Raptor engine and am running an ACME 2419 prop. When the boat is loaded up with 10+ adults or some ballast that it won't go above 3100 RPMs (about 17 MPH). Other times, it will do just fine. It doesn't seem like a prop issue because at times it will go to ~4k RPMs and into wakeboarding speeds, but often gets stuck at lower numbers when loaded up.

Any suggestions?

Thanks!

[Zackdogg]

Probably same thing I’ve had going with my RZX, since I’ve owned it. Just won’t plane out.. What elevation are you at? I’ve remedied mine somewhat, by running 500-600 lead in the bow, and dropping to a 10.5” pitch on my prop.


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[ynot]

I'm at about ~3600' - ~5600' (Utah)

I've considered using a 10.5" prop but am wondering if that will make much of a difference. I haven't run any lead in the bow, but have had 3-4 people there with the front ballast full and I'm not sure if it did anything for me. It seems like it there is some kind of an RPM or load limiter sometimes

[Thistledoo]

yea when its doing that move 6 adults in the front and see what happens...bet yea it will plane and rev

[UNSTUCK]

99% sure it's a prop issue. Well, the prop is fine, it just doesn't like your load and speed requirements. Welcome to high elevation boating, where we sacrifice top end speed for low end grunt.

My old boat had your same prop and I had no chance of getting to surf speed with full ballast and anymore than just my family of 5 on board. Nothing quite like a surfer, a driver, and 10 people piled up in the bow in a Utah lake. But don't worry, we all understand.


To verify your load limiter/rev limiter, next time you find yourself in this situation, just start dumping rear ballast. If it picks up speed you'll know it's a prop issue. If it doesn't it's time to look elsewhere.

[ynot]

What prop would you recommend? I asked the local dealer and they said an ACME 3091 (15" x 10.5") but that one looks harder to find now. Any other suggestions?

[Zackdogg]

Yep, you’re running at real similar altitudes to me, and Unstuck, and you can find some pretty detailed threads from both of us, about our experiences.. What motor do you have? How much ballast are you running??

I’m running the 2951. Just a little different cup. You probably can’t go wrong with either one. I had better luck, and cheaper buying a prop from Nettles in Texas, even than from Acme, themselves.

I’ve been through all of this, and that prop helped a bunch, but isn’t the ultimate solution. You’re top end will be gone, riding will be much improved. I run full ballast in the front, plus usually a couple of bodies, and 500-600 in lead, with the 10.5” pitch prop.. it sucks, and was a bad choice on gear ratio, if you ask me, but I have no choice but to deal with it, at this point.. I thought there was something wrong with the boat, for months, because I couldn’t believe it wouldn’t move the advertised weight.. I struggled a little up to about 4500, but can run all my weight now.. I still struggle over 5000’, and 6000’ I can forget about..

I’m working on figuring out how to switch to a 1:76:1, or 2:1 drive, right now.. either should help, quite a bit..


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[Zackdogg]

Yep, you’re running at real similar altitudes to me, and Unstuck, and you can find some pretty detailed threads from both of us, about our experiences.. What motor do you have? How much ballast are you running??

I’m running the 2951. Just a little different cup. You probably can’t go wrong with either one. I had better luck, and cheaper buying a prop from Nettles in Texas, even than from Acme, themselves.

I’ve been through all of this, and that prop helped a bunch, but isn’t the ultimate solution. You’re top end will be gone, riding will be much improved. I run full ballast in the front, plus usually a couple of bodies, and 500-600 in lead, with the 10.5” pitch prop.. it sucks, and was a bad choice on gear ratio, if you ask me, but I have no choice but to deal with it, at this point.. I thought there was something wrong with the boat, for months, because I couldn’t believe it wouldn’t move the advertised weight.. I struggled a little up to about 4500, but can run all my weight now.. I still struggle over 5000’, and 6000’ I can forget about..

I’m working on figuring out how to switch to a 1:76:1, or 2:1 drive, right now.. either should help, quite a bit..


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[Zackdogg]

We only wakeboard, early, on glass, and with maybe 6-8 crew, and don’t have a prayers chance at hitting 21 with any ballast.. you start running in the heat and wind, that elevation only gets worse, and you lose more power..


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[bsreid]

If you drop down to a 10.5” pitch your rpm will sky rocket and so will your fuel bill. You can only go do slow in pitch. Although because you’re stuck at 3100 it doesn’t seem like high rpm is a problem for you now is it. We had the same prop and couldn’t keep it any where under 4000.
Jumped over to a 16x12.5 prop which gave the boat much more power, just didn’t fully have the get up and go out of the water to reach speeds. Removed a ton of cup, can’t remember how much would need to look it up and made a world of difference. But yes we are at sea level.

[bsreid]

If you drop down to a 10.5” pitch your rpm will sky rocket and so will your fuel bill. You can only go do slow in pitch. Although because you’re stuck at 3100 it doesn’t seem like high rpm is a problem for you now is it. We had the same prop and couldn’t keep it any where under 4000.
Jumped over to a 16x12.5 prop which gave the boat much more power, just didn’t fully have the get up and go out of the water to reach speeds. Removed a ton of cup, can’t remember how much would need to look it up and made a world of difference. But yes we are at sea level.

[Zackdogg]

If I can get this gear change figured out, switching to a 16” prop is my first order of business.. I haven’t mess with it, yet, because I don’t want to have to buy another $900 prop, after I change those gears out. I tried to get ahold of Jim at Acme, several times, and never could talk to him directly, as well. I don’t know what pitch would be equivalent going from 15” to 16”..


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[ynot]

You are certainly more ambitious than me with that. I wouldn't know where to start withbtryong to switch the gears

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[bsreid]

Zach you know I have the same gear ratio as you and run the 16”.

[Bamer]

If I can get this gear change figured out, switching to a 16” prop is my first order of business.. I haven’t mess with it, yet, because I don’t want to have to buy another $900 prop, after I change those gears out. I tried to get ahold of Jim at Acme, several times, and never could talk to him directly, as well. I don’t know what pitch would be equivalent going from 15” to 16”..


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I figure a rough estimate to find equivalent pitch for different diameters is to calculate the surface area of a circle for both diameters, then divide one diameter by the other and now you have a ratio. Scale the pitch by that ratio. I did this when swapping my props and it came out real close to the rpm I calculated. 15-16 is about 13% more surface area, so scale pitch down by 13%. If your current prop is 12 pitch, then go to a 12*(1-.13)=10.44. Compare this estimate against the pros n let me know of it comes out!


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