ACME vs. OJ 4 blade

As most of you know, my new OJ, 13X13, four blade prop is toast. I can either get another OJ, 13X13, four blade or have them install an ACME prop.

For the short time I had the OJ, I enjoyed the power and smoothness. I've seen so many of you guys post topics on the AMCE 540 and 542. This makes me believe I should switch to ACME. I don't want to lose the power I had with the 4 blade. How does ACME line up against OJ, 4 blades? I ski, board and barefoot. I'm more of a power person versus speed. What prop should I go with?

Thanks,

Ken

I've got an OJ 13x13 4-Blade on my '79 and the factory Acme 12.5x15.5 on my '02 Ski 196. I have been very happy with the performance of both.

Ken, obviously I have a different hull, and Im running higher pitched props with the 1.23 tranny, but Ill chime in anyways.

The first thing I replaced on my boat (after my ignition that quit) was the prop- I went from a 4-blade OJ (13x16) to a 3-blade Acme (12.5x15). It was like a whole different boat- I picked up 200 RPM on the top end (4600 vs 4400), partially due to the decrease in pitch. I also picked up 1 MPH top end (43 vs 42 MPH). The real difference was in the holeshot and midrange power- the boat just responded 100% better with the Acme- it was smoother, and much quicker to accelerate.

A month after I switched, I got to drive my boat and our old '92 back to back pulling barefooters. The '92 has GT40 heads and an OJ 4-blade, so I was a good 40 hp down. Again, I couldnt believe the difference in the way the boats behaved. The '92 can do 46-47, but I know I would have beaten it to 40. Also, my boat pulled my 190 lbs barefooting at 41 MPH- only losing 2 MPH tells you the prop can bite! Like Stang says, if I take a hard corner and get on the throttle, the prop just digs in- very impressive.

I cant say enough good things about the Acmes, especially the 3-blades. I have heard all the testimonials here about the 540 and 542- and I wouldnt doubt them for a second. Greatest and easiest mod you can do to your boat.

Oh, and one more thing- Ive noticed no significant changes in the wake going between the 4-blade OJ, 3-blade Acme, and 4-blade Acme. If anything, the Acmes may lower the rooster tail a *touch.* 4-blades are supposed to be better than the 3's in this respect, but I just havent seen it.

The 542 has 1/2" less pitch (13x12 vs. 13x11.5), that is the difference between the props. SkiDIM says it will turn 150 more RPM than the 540, which sounds about right- I compared my 12.5x15 to my dad's 12.5x15.5 and noticed 180-200 RPM difference at WOT. If you call Bill at Acme, he can tell you exactly how your boat will perform with either prop. My guess is you would be happier with the 540 since you arent running ballast- but I would consult Bill to be sure. Anyone out there who's tried both?

I just found Keith's documentation on the ACME 540 13X12. That looks like what I want for my boat. Amazing how a prop can make all the difference in the world.

Ken

My top end has always been 42MPH. I'm wondering what the 540 would give me for speed at 4,400 RPMs. Now I'm weighing out my speed/power options. If I only gain 1 MPH, then I'd rather go with the 542. If I could kick it up to 46MPH, then the 540 sounds tempting.

Ken

I did a search on the 540 prop. Seems like a lot of people have purchased the 540 over the 542. I don't run at WOT often, but I will on occasion with bad weather rolling in. A few miles an hour won't make a ton of difference, but it's good to have. I don't weigh my boat down with fat sacs and people. I just want my transmission to sing nicely and my engine to be happy.

Ken

Mark,

I really appreciate your input. Sounds like you're happy with your investment. That's sells me right there. I don't want to get too crazy about the differences between the 540 and 542. I'll pick one, the 540 and be happy with it. I'm going to work on improving my barefoot abilities. The 540 sounds like it's better at high end.

Ken

A 540 will be on our boat next year for sure, I've read enough to convince me.

the oj 4 blade is my choice for the pull but mostly that arm hurting hole shot.after GT-40 heads engine turning too many r's, called eric told him make and application,send it back and he would make it RIGHT,this is what i do. boy he knows his stuff.but after all he makes those props.'64 amer. skier,PCM 302 4400 rpms top speed depends on weight but most days 50 gps is the norm. 3000 rpm needed for my parasail,eric gets all my bussiness,btw can you call acme and talk to the man that is going to repitch your prop, or ask him a question about his product????boat dr

Posted: July 12 2006 at 5:26am | IP Logged    

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FWIW, the prop that came on my boat was a 4 blade 18 p OJ. The boat would run 46 WOT (GPS)but only turn around 4100 rpms.
Upon talking with Skidim I learned the prop I had was too large. After discussing several props with them, two were at the top of the list. The ACME #422, and the OJ #428 XMP.
I bought the OJ because it was a little thicker and only a few $ more.
Now the new prop turns just under 5000 rpms and pushes the boat to 47.8 GPS.

Since the above post I've noticed how much more punchy the boat feels accelerating, pushes better through a tight turn, hole shot, and braking.

My .02 worth. d

Doesn't OJ have a little issue with the balancing being hit or miss? some are fine others need reworked some?