2001 VLX WOT low rpm

[Bujah]

2001 21' Wakesetter VLX with an OJ 14 x 18 prop (assume stock?). 

The most RPM I can get out of the boat is 4100rpm about 40-41mph (I keep it on a small lake so its plenty fast), which is under the 4600rpm WOT low threshold. The boat is new to me last fall, so I'm not sure if this is where it has always ran. It just seems a bit low. I'm just wondering if it is a condition of the prop or if I need to be investigating an engine issue. I'm trying to decide on a new prop to make it more surfable. But would like to know if it is running how it should be first.

[EchelonMike]

The 18" pitch is a very "speed" oriented propeller and I'd say is not an ideal prop for the boat.  The engine doesn't have the power to spin it to hit redline.  It's "over-propped".  

Depending on how you will use the boat, a propeller like an ACME 537 is probably going to perform much better all around.  something around the same diameter with a lower pitch value.

There are several good sites like Prop Depot, Wakemakers, etc. that can give you recommendations based on your intended use, elevation of your lake above sea level, etc.

Good luck and congrats on the new boat.

[formulaben]

Mike's right, you're definitely over propped.  When researching which prop you're going to get, definitely go up in diameter if you can. Measure the distance between the blade tip and the hull.  You want about 1/2" minimum or else you'll get prop burn on the gel coat.  My 2002 was able to go with 14.5" and probably would have fit a 15" prop if one had been available at the time of replacement.  IIRC with the larger diameter prop and ~12" pitch you can easily surf but still get around 35mph if you still wanted to slalom ski or go "fast".  But definitely DYOR for your particular model. 

[UWSkier]

Agreed.  Too much wheel.  13.5x17.5 was factory on those in the Acme 381, but that's not a surf prop either.  It's a great slalom prop and it's what we've run on my dad's '01 VLX (Sunsetter, same boat, just different hull tweaks) for 23 years now.  But for surfing, definitely prop down.  I wouldn't go any bigger than 14" on that older hull design.

[butter71]

26 minutes ago, UWSkier said:

I wouldn't go any bigger than 14" on that older hull design.

You can probably go up to 14.5" diameter.  Have been running an Acme 1235 (14.5 x 14.25) on our 2000 LSV for 300+ hours, with sufficient clearance and no evidence of gel coat burn.  Would expect the VLX to be similar, but check to be sure, as suggested above. 

On the other hand, an Acme 537 (13.5" x 16") would still be a step in the right direction, and they can be found fairly cheap these days if you keep your eyes open.

[Bujah]

Thanks a lot for all the replies and prop advice.

What's the opinion on an Acme 1847? Not a lot of discussion on here about that one. I only ask because I have a line on one for a good price that's been refurbished. Or is it just better to start with a new prop? 

I have read about the 1235 and 1939. But, how's a guy to know? The boat is already set up with a wedge, Lenco surf gates, 1000lbs of rear ballast and the stock MLS in the ski locker. This is the setup that was in the boat when purchased, surprised about the prop that is on it. I haven't had a lot of time to test everything out yet. As soon as the boat was put on the lift this spring it has not stopped raining (which is ok because the lake was way down). My plan is just causal activities, no pros here. Would just like to be able to surf, occasional slalom (just for pleasure), kids tubing, I still like a knee board face plant every now and then and just tried wakeboarding last fall and plan to continue that.

 

[cowwboy]

I have a 02 vlx and run the 1100's in the back lockers and a tube bag in the center. I run a 2419(15x12) or 2315(15x12) for surfing and a 381 for poker runs and cruise days. I got the 2315 used for a great deal or I'd have just stuck with the one 2419. 

For your ballast I would suggest a 15"x12" for surfing. 

The 1847 (14x14.25) looks to be a bit to much prop pitch for surfing with your ballast set up. 
 

Have you talked with your local prop shop? 

[butter71]

17 hours ago, Bujah said:

What's the opinion on an Acme 1847?

I think it'll probably work fine for you, since you've found a good deal on one.  As mentioned above, we run an Acme 1235, which has the same diameter and pitch (14.5 x 14.25), with a little less cup, and we surf with very similar ballast setup as you described.  Never feels like we're overworking or lugging the motor when surfing, but still have enough top end for occasional slalom runs.  This, on a 2000 LSV, w/o wedge, so maybe not the perfect comparison.  Also, if you double your rear ballast up to the range @cowwboy runs, or with the wedge, then maybe I can see it being overpropped a bit.

[Bujah]

Thanks for the insight.

I have not talked to any prop shops yet as I want to make sure it's running tip top and get a feel for how it's performing.

Last time I was out I heard what seemed like an arcing plug wire. Checked them all and could still here it. This morning I replaced the plug wires along with a very fouled up cap and rotor. This made a world of difference. I was able to hit 4400-4500 rpm and it really smoothed out the rpm range to wot.

 

I will make some calls this week and see what the prop pros recommend. 

I have read a lot of comments that say to go with a 1235 but will definitely look into the 15" proprs.

[Slurpee]

537. Did us right in everything for 16 years with that boat.