Need Help With Vent Holes for RX4 Prop

[mactlman]

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

yes 3500-3700 no more no less tournament load best so it is in the best spot for worst conditions--temps and humidity will also play out in the summer on venting will need more maybe

[BigBass044]

Finally got Out with the New Prop Today and Ran it with all the vents all the way open, and am pretty happy, the boat handles much better and rough water seems way easier to run. Holeshot is much faster, I even gained 5mph top end speed. I’m right in the middle at 3600 RPMs at Holeshot. WOT tho the most I was able to get it to was around 5300. It was pretty rough out on lake conroe today so I’m hoping to test on a calm day to see what RPMS i can get out of it. if I can’t get that 5600-5800 then what should I do?

[mactlman]

Finally got Out with the New Prop Today and Ran it with all the vents all the way open, and am pretty happy, the boat handles much better and rough water seems way easier to run. Holeshot is much faster, I even gained 5mph top end speed. I’m right in the middle at 3600 RPMs at Holeshot. WOT tho the most I was able to get it to was around 5300. It was pretty rough out on lake conroe today so I’m hoping to test on a calm day to see what RPMS i can get out of it. if I can’t get that 5600-5800 then what should I do?

venting has nothing to do with max rpms. is ptp about 3.25-3.5? if you are that low on rpm's now it will be way bad in the heat. 200hp is not enough for that big hull so you will have to adapt and live with it. maybe marks propellers can turn it into a 23p? call him if you need prop work

[BigBass044]

Yes it’s about 3.25. When I was at 5300 it felt like I could get more out of it,it Boat would start to lift a little which is something it never used to do with the 3 blade, on a calm day where I can just floor it and trim it right I think I can get more out of it, running couldn’t really run it the way I wanted to in rough water, when I was testing it out it was about 65-70 degrees out here in Texas so not too cold. I’ll definitely talk to Mark, thank you. Do you think re working it to a 23p wojld help?

[mactlman]

Yes it’s about 3.25. When I was at 5300 it felt like I could get more out of it,it Boat would start to lift a little which is something it never used to do with the 3 blade, on a calm day where I can just floor it and trim it right I think I can get more out of it, running couldn’t really run it the way I wanted to in rough water, when I was testing it out it was about 65-70 degrees out here in Texas so not too cold. I’ll definitely talk to Mark, thank you. Do you think re working it to a 23p wojld help?

mark will know need to see what the max rpm's are floored and properly trimmed mark will need this info

[H2OSprint]

BigBass, did you ever get your RPMs up over 5300. Have the prop reworked? If you water pressure remained above 18 psi or whatever your motor likes, I would go up another 1/4. I've heard that the 4 blades can run higher. I am trying a RX4 25 this week. I know this thread is not fresh, but I might be looking for some help dialing it in. I have Evinrude Vindicator on a 20' Stratos.

[Bassmeister]

The 3.0 vindicator just does not have the grunt at low end the 3.3 DFI engines do.... I myself kinda like the Bravo props by Merc myself.....

[H2OSprint]

The holeshot was about 7-8 seconds with the RX4 25P, maybe I need to drill 4 more vent holes like the guy mentioned on page 1. It ran 5400 at 59.5mph.
With my water PSI at 31, I would think I could go up 1/4", maybe 1/2" on JP? I'm also trying a 25P Tempest Plus next week. My old 24 Raker wants to run too many Rs.

I've heard that Tempest Plus can run a little higher on JP than Rakers, do you think that is true?

[mactlman]

The holeshot was about 7-8 seconds with the RX4 25P, maybe I need to drill 4 more vent holes like the guy mentioned on page 1. It ran 5400 at 59.5mph.
With my water PSI at 31, I would think I could go up 1/4", maybe 1/2" on JP? I'm also trying a 25P Tempest Plus next week. My old 24 Raker wants to run too many Rs.

I've heard that Tempest Plus can run a little higher on JP than Rakers, do you think that is true?

are you getting up to 3500-3700 rpms on take off? need to have ptp about 3.25 inches below also need to measure ptp accurately and mark jack plate also, is what I did