Need Help With Vent Holes for RX4 Prop

[BigBass044]

Hello all, Just picked up a New RX4 15x24 Pitch Prop For My Ranger Z520 with a 200 Horse G1 E-Tec H.O. The E Tec came from the factory with a Raker II 14 1/2 26 pitch Prop, that prop has no Vent holes, The RX4 prop does, I’ve never ran a prop with Vent Holes so they are very new to me, where do I start? How do I adjust them? And any sweet spot recommendations from others with similar Setups? Also will the Current TBX hub I’m running On the Raker II fit the RX4? Thanks guys

[Bighare2]

Yes the TBX hub kit used on your Raker will work on the RX4.
Vent holes - fixed size or adjustable are used to help acceleration out of the hole. Vents allow a controlled seepage of exhaust in to the prop blades to allow the prop to spin up quicker on acceleration. Testing and experimentation is the only way to determine what works best for your rig.

Look at the vents and you will see a small torx head screw used to hold the vent plate in position. I do not remember the Torx size/number. Loosen the torx screw and rotate the black vent to alter the vent size of more or less opening. You will see and feel some knotches that prevent the vent from slipping. Don’t over torque when tightening.

Start with the vent closed and perform a couple of timed accelerations from zero to 10 seconds.
Go back and loosen - not remove- the torx screw and open each vent one knotch. Repeat the timed test.
As you progress the time from zero to 10 should get faster.
You probably need to do this only 4 times to determine what opening works best.
Good luck

[BigBass044]

Great information, thank you! What RPM am I looking for Once I get up on Pad? I believe it is 3500 RPM but am not sure. Now when I go to Open the Vents to do the 10 second test, each time do I open each vent a notch? Or only one vent a time for each test? Thank you.

[Bighare2]

Adjust all 4 vents.
You can Count time to plane or time to 25mph. Whatever is easiest. Rpm is not relevant.

[BigBass044]

Great Info Thank you for the help, I believe the RX4 will Lose me a Few MPH and Use a bit more gas, but will be much better in rough water and handle much better than the Current Raker II I’m running, down the road do you think it would be worth it to have A Prop Shop Drill Some holes in the Raker II and install some Vents for faster hole Shot? With the Raker II my hole shot isn’t the best and I plan on Running that prop when I’m fishing Smaller lakes that don’t get very rough.

[Bighare2]

The Raker II for sure can be drilled to add vents. But there is nothing available to make the new holes have a variable size port. 1/2” to 9/16” was the typical fixed size hole.
you have not indicated what your wot rpm is at best trim and best top mph. And you do not yet have any comparison data from the RX4. Meaning there is not enough information to make a judgement for the future. Plus there is no information on how the engine is setup on the transom.
The Raker 26 is a tough prop to turn on a 200hp. I would be surprised If there is much loss of rpm with the RX4.

[BigBass044]

Gotcha, good to know. My Best wot Rpm is 5300-5400 at 55-56 MPH With the Jackplate All the Way down and Trimmed Up. Do you think I’ll lose some RPM with the RX4 or Gain some? I know my engine should be at the 5700-5800 RPM range or close to it, but with the Raker II 26 I just was never able to do it, a prop man that recently passed away Recommended the RX4 15x24 pitch for My E Tec but since then I was never able to get any more info from him regarding the setup.

[Danrude]

I am running a Raker HO 14 1/2 22 on my 200 G2 and it turns 5850 RPM's it comes with with the vent holes in it. I also run a RX4 15 X24 at 5700. I agree with Bighare2 the 26 is too much prop for the 200 but you should be able to dial in the RX4.

[BigBass044]

Awesome info, thank you! What boat is your E Tec on? Also what Do you have the Vents set to? Just for a general idea. Thank you!

[Bassmeister]

Is your 200 E-TEC an HO? Dan's is and will make a difference if yours isn't....just an fyi....

[BigBass044]

Yes sir it is a 2012 Evinrude E-Tec 200 H.O but it is not a G2 like Dans, it is the original G1 E-tec, does the different Generations make a difference?

[Bighare2]

Why are you running the jack plate all the way down? Seems counter-intuitive. My guess is a a big loss of top speed.
Your engine likes 5600 5800 wot rpm.
knowing this new info I bet once you run with the jack plate higher you are going to like the RX4. Expect better/easier drivability at speed, regardless of water conditions and driving over wakes of other boats.

[Danrude]

Sorry I missed that, on my old E-Tec gen 1 200 I ran a 24 Raker (no vent holes) turning 5800 at 2.5 below pad!

[mactlman]

Great information, thank you! What RPM am I looking for Once I get up on Pad? I believe it is 3500 RPM but am not sure. Now when I go to Open the Vents to do the 10 second test, each time do I open each vent a notch? Or only one vent a time for each test? Thank you.

fully tucked under and floored, it needs to get up about 3500 or so even 3700 ok but not more or less to have a good holes shot

[mactlman]

Gotcha, good to know. My Best wot Rpm is 5300-5400 at 55-56 MPH With the Jackplate All the Way down and Trimmed Up. Do you think I’ll lose some RPM with the RX4 or Gain some? I know my engine should be at the 5700-5800 RPM range or close to it, but with the Raker II 26 I just was never able to do it, a prop man that recently passed away Recommended the RX4 15x24 pitch for My E Tec but since then I was never able to get any more info from him regarding the setup.

motor needs to be about 3-3 1/4 below pad when running down the lake find this height on your hyd plate

[BigBass044]

Yes sir, My Top end is about 7-10MPH slower if I’ve got the jackplate jacked up a few inches, so I’ve always just ran it All the way down Unless in shallow water, I’ll be trying out the RX4 next week and will give back my Results, thanks for all the help!

[rgoss66892]

Hi,
I am running a 25 pitch RX4 on my 2014 Z521C. I have a 2014 250HO G1. Be aware that the Rx4 was developed for the G2 which has much better low end torque than the G1. I found that there was not enough venting on the prop with all vents fully open to allow the prop to spool up enough rpms to get the boat on plane easily. I drilled 4 more 1/2 holes in the prop in order to provide more venting. The boat has a good holeshot and will run 70 MPH (light load). The RX4 is a grip monster and needs the extra venting when used on a G1.

[BigBass044]

Great information thank you! I still haven’t been able to Get out on the water and try the prop out. I’m planning on giving it a try in a week. I’m most likely going to end up getting some more holes drilled in it. Do you recommend Just Opening all of them all the way Starting off? Also what RPMs are you running boss?

[rgoss66892]

Yes, Start with all holes open. If you can't get the rpms up on holeshot you will probably need to add holes. I run with all holes open and the four extra 1/2 inch holes. It works well for me. I run 5900 at WOT.

[BigBass044]

Perfect thank you, I believe I’m supposed to be at around 3500 rpm’s on Hole Shot, is that correct?