Speed, RPMS, Prop, and Performance... I'm concerned about my boat's performance

[skisky89]

I picked up a 2004 X-10 with the Predator engine in July, and after the test drive and the trailering home.... the boat had an awful shake out of the hole. I pulled it out of the water immediately and replaced the drive-shaft strut bearings, and had the prop tuned.

One of the strut bearing slid out of the strut!! The local prop shop had fowl things to say about the condition of the prop to...

Now I have a smooth hole-shot, the engine seems to run well.... but I'm noticing a couple more things that are 'off.'
At cruising speed the boat seems to pull or roll to the port side. Also, my WOT RPM will only hit 4100 at about 39mph. This can't be right.... right?
Hole shot isn't awful, but I feel like it should be better. The prop shop said I'm at 13.75" diameter and 19" pitch. I'd like to make sure everything else is correct before I try a 17.5 pitch prop.

Is anyone experience with this hull/engine combination and the performance I should expect? My previous boat was a 2001 centurion eclipse direct drive.

[jpwhit]

How many hours on the engine? Did you have a compression test done before buying? What are the compression pressures for each cylinder?

[waterlogged882]

Pull to the port side is normal.

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[lakedrum03]

I picked up a 2004 X-10 with the Predator engine in July, and after the test drive and the trailering home.... the boat had an awful shake out of the hole. I pulled it out of the water immediately and replaced the drive-shaft strut bearings, and had the prop tuned.

One of the strut bearing slid out of the strut!! The local prop shop had fowl things to say about the condition of the prop to...

Now I have a smooth hole-shot, the engine seems to run well.... but I'm noticing a couple more things that are 'off.'
At cruising speed the boat seems to pull or roll to the port side. Also, my WOT RPM will only hit 4100 at about 39mph. This can't be right.... right?
Hole shot isn't awful, but I feel like it should be better. The prop shop said I'm at 13.75" diameter and 19" pitch. I'd like to make sure everything else is correct before I try a 17.5 pitch prop.

Is anyone experience with this hull/engine combination and the performance I should expect? My previous boat was a 2001 centurion eclipse direct drive.

Assuming your gear box is ~1.5:1, then a 19" pitch prop seems crazy high, especially with the Predator engine which I believe was 310hp. For comparison, my 205V variant (smaller boat) with the MCX (350hp) and the 1.56:1 v drive came stock with a 14x18 prop and I could peg the speedo at 5000 rpm.

With that, I have no doubt that 4100 rpm would be about 39mph with a 19 pitch prop, but I bet it takes a while to get there. I went to a 14.5x15.5 (Acme 2061) which has great hole shot and current top speed is about 42 mph at WOT. I surf at about 2600 rpm, wakeboard about 2800 and cruise about 3200.




EDIT: Wakemakers recommends these props:
Cruising: OJ WakePro V3 812 4 Blade 14.75" x 15.75" Propeller
Wakeboard/Surf: ACME 1285 4 Blade 14.5" x 14.25" Propeller (this is a fan favorite around here)
Heavily weighted surf: ACME 2195 4 Blade 14.5" x 12" Propeller

[robadele]

I run a 13.5 x 17 prop on my 99 Maristar 210, so nearly the same hull. Top speed is just over 40 at max. As a note, the water has to be really smooth and the boat trimmed out correctly to get up over 40, otherwise any wave chop slows it down. Hole shot is good but even this prop has too high a pitch for surfing a lot. You should drop to a 16 if that’s your intended use.

[skisky89]

How many hours on the engine? Did you have a compression test done before buying? What are the compression pressures for each cylinder?

jpwhit 231 hours at purchase. 256 hours now, should have done a compression check! I'll do one and replace the spark plugs while I'm at it.

[skisky89]

Thank you lakedrum03 and robadele !!

Looks like I'm prop-shopping. I do about 75% cruising and wake-boarding, the rest is pulling the kids on whatever is cool this week (tube, skis, kneeboard.)
Sounds like the ACME 1285 is what I should look for. I'll report back after some progress.

[skisky89]

lakedrum03 , is there a spline cross-reference for the ACME 1285?

Woops, found it!

https://skidim.com/1285-14-5-x-14-25-105c-4-bld-splined.html

[bturner2]

Good post and advice from Lake as always. Both Acme and OJ make excellent props and I've owned both. Eric at OJ is my go to person for prop recommendations and I call him before I buy any new prop. Do yourself a favor and call them before doing anything. Prop are to expensive to guess with IMO.....

https://www.ojprops.com/

[skisky89]

Absolutely, I've got some questions about 'cup' which I understand to be the cup at the tip of the prop blade. This prop intrigues me, can I have better whole shot and some cruising efficiency?:
https://skidim.com/1479-14-5-x-14-25...d-splined.html

[bturner2]

My personal experience has been that there is no free lunch with props (and apparently at Twitter now as well). Efficiency? Sure some but nothing that will knock your socks off. When I was into "go fasts" picking up a mph was something you'd be willing to pay big money for. On these boats, no so much. These are basically for the most part tractors so anything over about 45 is considered respectable. Hole shot is most time preferable and if you can find that one right prop with a bit of both you have the golden ticket. The boat I have now is running a prop that basically fits this description. On my previous 07 X2 I ran 2 different props as we used the boat in 2 very different environments. We split our time between an inland lake and Lake Erie. On the inland lake we ran a surf torque prop as that's all we really used the boat for and speed or fuel efficiency really didn't hit the radar for importance. On lake Erie where I was typically 10 to 12 miles from the launch and where the weather can change at a moments notice, fuel efficiency and speed if only 3 mph can make a big difference. As such before you go buying another prop you really need to think about how and where you plan to use the boat before jumping in on a new prop. Or if you're going to be boating in different locations you may want to consider doing as I did and switching props based on intended use.

[waterlogged882]

Absolutely, I've got some questions about 'cup' which I understand to be the cup at the tip of the prop blade. This prop intrigues me, can I have better whole shot and some cruising efficiency?:

Nettle Props and / or Wakemakers are a couple of places to shop for propellers.

.

[jj91]

I have a 2004 X2 with the predator engine. Not the same boat but similar in length and dry weight. 4-5 years ago when I was prop shopping my local Mastercraft was very much of the opinion that ACME props performed better than OJ. I know OJ has released newer versions of their props so maybe that’s not the case anymore. And from what I’ve read OJs customer service is off the charts. I know the MCX gets all the love (and I do think that red looks awesome) but the local dealer was very much under the impression that torque curves on the two engines were similar and advantage of the MCX was top end due to higher max RPMs. To a certain extent you have to pick your poison...do you want more top speed or to pull stumps? I upgraded from the stock (OJ 13.7 x 19.5) prop (top speed ~43-44 mph on gps). I’m at about 1000 ft elevation. I was looking for something with better holeshot and could handle the weight better, but also wanted to keep most of the top speed. Prior to talking with ACME I was looking at the 14.5 x 15.5 (2061) prop. They actually recommended the 14.5 x 16 (1593) as they thought with the 15.5 pitch I would be hitting the rev limiter with the predator engine. I went with the 1593 and have been very happy with it. I run about 2,200 lbs of ballast (750s in the rear, KBG, IBS) + 3-6 people in the boat and it can get up to surf speed without a problem. I’ve never pulled a wakeboarder with full ballast (none of us are that good) so not sure if it would get on plane with full ballast and people. If I’m empty and at WOT I can still hit the rev limiter ~42 mph (per my gps perfect pass)…only do that when I pull my one buddy who foots.

[86Skier]

4-5 years ago when I was prop shopping my local Mastercraft was very much of the opinion that ACME props performed better than OJ.

My suspicion is that dealer sold ACME props.... and that salesman... was being a salesman.

That said... ACME and OJ both make good wheels.... but, if it's up to me, I'm calling Eric @ OJ every single time. If it's truly a prop issue, he'll set you up. Just call him and explain what you're seeing.

[skisky89]

I'm glad that I went with the ACME 1593 for the Predator 5.7L, I had very exceptional hole shot with full ballast and 8 people on the boat last weekend. I still have a comfortable cruising speed around 3000 RPM with plenty left in the throttle. Any less pitch than and I'd be screamin' to hit 30 MPH. Perfect pass also performed better.

What I didn't expect (but happily gained!) from this prop was handling. Much better handling at low and high speeds. More control at idle and while backing up and maneuvering around the dock. Also no noticeable roll to port above 30 mph. I'll test WOT next trip out with less people on board. My local CompuProp shop says we can add cup to the prop to add top-end load if I'm hitting my redline with a lot of throttle left.