Question re RPM's/slip and Fury 25

[ChuckHannaford]

On my last two Ranger 520C with Merc 250 ProXS Gen II lower unit...Max RPM's in summer 5050 and it is set up right on 8 inch Atlas Hydraulic plate. 25 Fury B and B by Mark with a little extra cup. Handles great but hole shot is sluggish with two and live wells full. Max speed on this boat (2017 520c) loaded is 67 mph with two fishermen and live wells full. Max speed by myself is 70 (engine has 13 hours on it). I sent Mark a new 25 Fury to de-pitch and B and B.

My 2015 520c would max with me alone at 73-74 and 70 with partner and live wells. Someone mentioned that they may have detuned the 250 ProXS this year...

[fishfarm]

Mercury doesn't go by years only serial number. I have same engine as you with a 25p fury turning 6050 and 75.8 with me alone and 50 gallons of fuel and full tourney load and partner 73 at 5850/5900 r's. Running at 2.5 under pad. You should have had no problems turning a 25p fury

[z520brewer]

fisharm you are running an oversized motor on your boat aren't you? The results you are seeing aren't typical for the z520 series or a 520vx with properly prescribed motor are they? just wanting to clarify since many will read the post and be expecting more than they can achieve with their boats. thanks,

[trapp201pro]

He is running a 250 just as the original poster is.If 5050 is max RPMs I hope it is a misprint. The 250 pro XS was detuned in 2013.z520bewer what is the max horse-power for a z520 ?

[fishfarm]

Ya be he is only spinning 5050 rpm's in the summer and tourny load is 67mph. He should be doing better than that with a stock 25p. fury. Theres Z520's all over the Ranger page gettitng 70/71 loaded and 73/74 solo and light

[ChuckHannaford]

Well, so far I have not heard anything helpful or that I don't know. Not trying to be rude but the reason I posted is because I know I should be getting more. I either have a Smartcraft gauge problem that is not accurately showing RPM's or some other issue. If you refer to my post, my 2015 ran the right mph but still showed less than ideal RPM's. So, I'm looking for suggestions other than sending a new prop to Mark...one is on the way. My current setup handles great, mid-range is good, and OK in every other respect except RPM's and hole shot.

[fishfarm]

What is your prop to pad a measurement that has everything to do with your whole shot and your rpm's I have heard that the fury can be inconsistent me including a couple Z guys are getting our best results running the Fury a little high so I'm like at so I'm like a high some of us are running good at 2 3/4 and 2 1/2 under the pad

[fishfarm]

Oh yeah another big factor do you have power poles or talons on your boat if you do you might be better off going with a four blade like a bravo XS or Razor 4XL to get more stern left

[ChuckHannaford]

fishfarm, thanks. I do have poles and am at 2.5 below pad. I know I'm running motor very close to sweet spot. I will certainly consider the four blade when Mark sends prop back and I test it out. The one I'm running right now is one he worked that was B and B'd and he added a little cup (25 Fury). I have a hydraulic Atlas jack plate, throttle has been checked to make sure it is all the way open etc. Last years boat (same set up) was faster.

[fishfarm]

Yup sounds like your in the sweet spot. I ran a 24p Razor 4XL on my rig and it was by far the best handling prop. Real good on hole shot and mid range and running rough water. It topped out at 71 but I run light. 25p Bravo XS sounds like a good contender for you as well. When ever you get into these 4 blades with 8 holes they are a pain in the azz to setup but once there dialed in they run sweet.

[fishfarm]

Max hp on a z520 is 250hp. I wouldnt really say they were detuned its more like retuned to burn E10 better per Don Weed on the Merc forums trapp201pro

[mdtritn21]

They were detuned to meet CARB spec in 2013 by about 8 hp. They are running about 262 hp now. If your only turning 5050 rpm's your down one cylinder and need to take it back to the dealer so he can run it on a diagnostic check on it. A bravo xs is the best prop on that boat.

[fishfarm]

This I can agree with on being down a cyl ^^^^^^^

[ChuckHannaford]

That should have read 5550. Sorry. All cylinders firing just not turning the prop as fast as needed.

[mdtritn21]

If it's only 5500 there is still something wrong with it. It could be down one cylinder or the throttle plate isn't opening all the way or it could be a fuel delivery problem. I'd take it in and have the motor checked. It could be as simple as a spark plug wire unhooked.

[ChuckHannaford]

All been checked. Throttle plate open and all cylinders firing.

[Ky 520c]

Mine runs about the same, rpms in the heat usually 100 give or take more than yours but I'm like most in that I'm running 70 w2 and load, solo 73. Not sure why you added cup mine lifts like crazy and I have pp's. I would try a few different furys. 16 model

[Legendboy13]

Sounds like a turned sleeve in one of your cylinders. My 250 pro xs did it. Mine would only run about 54-5500 rpm wot

[ChuckHannaford]

How does one determine there is a turned sleeve? If that is the case then my 15 with same set up and prop had one too.

[Legendboy13]

Good Mercury tech. Pull your plugs. If there is a turned sleeve you'll have a plug that is way worse than the rest.