Ok, Running a 25 Tempest that I had on my 2cylinder Pro Xs. Was told this is a good prop to break in engine with, but looking for a 23 pitch to put on after 10 hours. My question, is there a good prop other than a Fury 23, cause they are pricey. Thanks, not cheap but 700 bucks for new prop is a killer! Thanks for any and all comments.
what boat ?
why would you want to go down in pitch from a 25 to a 23 ?
See posting above for Rothwell Marine for better pricing on props.
Ranger Recommended, as well as dealer, on new 4 stroke.
Believe I would see how well the 25 pitch performs on your rig before spending money on a smaller prop... if that 25 gets the new (broke in) 4 stroke into the upper rpm range you may need to go up in pitch to reach the full potential of that V8.
I've seen several posts advising new 4 stroke owners to drop down one or two pitches from what they ran on the same hp 2 stroke Pro XS. That defies logic to me.. The new 250 Pro XS V8 is putting out 40% more torque than the 2 stroke it replaced.. Odds are your old 250 had 1.62 to 1 gears where as the new 4 stroke has the 1.75's.
I still have my old boat that is powered by a 2 stroke 300XS My new rig has a V8 250R with 1.75 gears.... Even with a 50 horse handicap that new V8 torque monster will turn the SAME props I was running on the 300 and get out of the hole faster.
Break the motor in and then see how many rpm's it will turn fully loaded ready to fish and then you'll have a better idea of what size prop you need. If it won't turn the 25 tempest into the 6000+ rpm range you'll need a lower pitched prop. Normally you gain 200 rpm's for every inch drop in pitch. I doubt he was running 1:62 gears on a Ranger.
My understanding is the lower unit for the 4 strokes is much more efficient than the Opti's which greatly reduced the amount of prop slip. The new motors put out more torque for sure but with alot less slip thus the need for a lower pitch prop. That coupled with the higher redline for the 4S reinforces a lower pitch is the right way to go. Still have a few months before I can run mine but everyone tells me the 23P is the right prop....at least for a heavy Ranger.
Last edited by Bassin Bob71; 01-24-2020 at 07:54 PM.
2019 Ranger Z520C DC / 250 Pro XS 4 Stroke
Can you explain how less prop slip equates to needing a smaller pitch?
Also my new 4 stroke has a lower rev limit than my old 2 stroke.
Repowering my Phoenix 721 from a 250 SHO to a 250 Merc 4s and talked to Mark Croxton yesterday regarding the best prop for that rig. He recommended a Fury 24 pitch. I'll start with that and see how it goes. He's been pretty accurate with other recommendations in the past.
Most guys I know running the new Merc on Rangers are using a 24 Tempest or 23 Fury. I don’t think you will be able to get the rpm’s where they need to be running a 25 pitch prop.
You run the smaller pitch props to get the rpm's up as close to 6200 as you can on the new 4 stroke motors.
I've also heard the exhausting through the lower unit on the 4 strokes does not vent the prop as well,so you can't get enough slip. Makes some sense as the same size 4s would only put out half the exhaust, as the cylinders fire every other revolution.It would take twice teh CID 4 stroke to equal the same exhaust venting as a 2 stroke. (3.0 2S = 6.0 4S).
And although the 4S makes more torque, it's in the midrange, not the bottom end. Add to that 4 valve heads are notorious for poor bottom end torque.
Most four stroke don't need the slip that's why they can use solid props without PVS holes drilled in them.
Was testing with a 28 pitch Max 5 prop on a 250R.. Pulled 2 of the PVS plugs and it spun so bad it went to guardian mode. Even a 30 pitch Promax will run with all holes plugged.. These V8's have a ton of low end torque when set up right.Originally Posted by mdtritn21
Because its more efficient. If you run a 25 and have say 10% slip, not sure if that's good or not, you really have a 22.5. Since the new 4 strokes have less slip , say 1 or 2%, then a 23 runs more like a 23. If you put a 23 on the old 2 stroke with 10% slip in theory it's like a 20.7. Get it?
Can you explain how less prop slip equates to needing a smaller pitch?
Also my new 4 stroke has a lower rev limit than my old 2 stroke.
Last edited by 96ranger492vs; 02-05-2020 at 06:13 PM.
No sir I don't !
Less slip to me---means the prop will run faster at the same rpm.
Lets plug your slip numbers into Mercury racing's prop slip calculator ….. A 30 pitch prop turning 6200 rpm's with 1.75 to 1 gears at 10% slip should run about 91 mph.
That same setup getting 2% slip should run 99 mph.
However more realistic slip numbers would be 12 and 6.
No it means you will run about the same speed at a lower rpm. thus the need for a lower pitch that will get the engine to the rpm that it makes peak horse power. These motors peak at about 6200. Two stroke 250PXS at 5950. Pro xs with a TKII case and the new four strokes are both capable of achieving 5% slip numbers with a perfect setup, I have heard claims of a little less, I am skeptical at present of the average bass boat achieving 5 percent
With the older TK1 or standard case I was very pleased to get the slip down to 8% tournament loaded, With 250psx two stroke TKII case I get down to 6% running the same props and loads, quite sure light load would achieve 5%. My rig is quite a bit better than average though
Thank You Leon Pugh
24 pitch fury 4 on my 2019 z520c merc 250 4s - love it
What are your numbers with the 24p fury 4? I have the same rig as you but with the 23p fury 3. Thinking the 24p fury 4 might be the way to go. Thanks
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