motor want turn up

[Phoenix 5]

I have a 2023 225 pro xs serial number 3b138337 around 85 hours on it. This motor will not turn over 5750-5800 no matter what prop I have tried over the last year. It's like there is a wall there. I have run a 23p and 24p tempest, 23,24,25 pitch fury3 and a 24p fury 4. Everyone of these turn with in 50 -60 rpms of each other. I have had my throttle demand check by 2 different dealers and both show I am get 100 percent throttle. I have hydraulic plate I have ran it up to the point of losing prop bite and water pressure no effect. Is there some other reason my motor will turn up? FYI these rpms are from a smart craft monitor. Motor seems strong until that point in the power band it just quits pulling.

[SOUTHERNYANKEE]

Same thing here. 225 4s 5800 max.

[Welaka]

My fishing partner had the same problem. Went to a 21p tempest plus. 6100 rpm and gained 3 mph These motors like small props, and run well with them. Too much 2 stroke advice still around lol.

[EuropeanAM]

Phoenix 5: What boat, jackplate size, BATTERIES/TYPE, and gear on the bow of the boat?

[mactlman]

Tried a 21p or 22p? Tempest plus or fury 3?

[Phoenix 5]

No that pitch should be way small for my setup. I had the same hull with a 200 otpimax turn a 25 all day 5750. this motor has 25 more horse power and want turn a 23 but 5800. I realize apples to oranges 25 horse power is 25 horse power. I plans well with every prop I have tried listed above and pulls strong but it just hits a wall at 5750-5800. It is like the time is advancing correct or fuel is turning down at that rpm range for some reason. Something just is not adding up. I am running a Phoenix 919 10 atlas plate, 3 lithium trolling batteries, 31 agm cranking battery, moderate tackle with all the heavy stuff in the rear storage. Have a 36 volt ultrex, mega live and mega 360 with 2 helix 9s. The boat lifts and rides good just top end struggles. Most people with this setup are get 74-77 mph.

[mactlman]

4s needs 2-3 less pitch on same hull than the 2 s---Basscat puts a 22 pitch on the 225 four stroke mercs on a caracal. . There’s no reason that shouldn’t work on your boat. Also the 919 is real close in size to a caracal. Mine has a 23 fury and stops at 5800 or so also. 67mph

[Welaka]

21 p tempest will fly. The 4 strokes like at least 3 less pitch.

[Phoenix 5]

Phoenix 919 xp with a atlas 10 inch plate. I have raised the plate to the point of losing water pressure and prop bite which cause speed lose.

[mactlman]

As others have stated above, there is a significant gearing change from the 2-stroke Mercuries to the current/new 4-strokes, which means that 2-3 inches *less* propeller pitch is required in order to turn the necessary rpms to achieve maximum performance. My guess on that hull is a 22 pitch 3-blade for best performance. Many/most of the Ranger Z519 come with a 21 pitch Fury 3 for that engine, and the Phoenix is a slightly lighter hull. Of course, how the boat is loaded and how that load is balanced also makes a difference. 225 horsepower is indeed 225 horsepower, but gear ratio determines how that horsepower translates into pushing the boat.

Also 225 hp on a two-stroke was probably more like 240 but on the four stroke they’re kind of calling it closer to what it actually is instead of staying under the 10% rule like they used to do a lot on the two strokes. My 225 ranger has a 23 pitch fury on it from the factory and stops about 58 5900 RPMs at 67 mph but I really haven’t messed with it yet for top speed.

[EuropeanAM]

As others have stated above, there is a significant gearing change from the 2-stroke Mercuries to the current/new 4-strokes,

As has been clarified MANY times, the GEAR RATIO for the V8 models remains 1.75 for the Standard Production ProXS models. The difference is in the gearcase geometry and a substantially LOWER slip coefficient.

It's important that folks realize the gear ratio didn't change (otherwise it's impossible to accurately figure prop slip).

[Mahomee]

Why do you want to turn it up?

These 4s have tq, you can feel it in the 5000-5700 rpm range. You dont need to run them near the red line.

My boat gets its max speed and has the best throttle response to work waves etc at 5500-5650 max rpm.

I put a 23-4 fury on it and that gets it to 6200 rpm and minus 6mph and it feels completely flat and dead almost exactly like a 2s.

[Phoenix 5]

Mercury like them to be close to 6000 rpm. My guess it they don't want it lugging. I did speak with a tech at a tournament last week in the service yard. He said could be some in the pcm possibly. He said he had see it with a couple of 250s.

[EuropeanAM]

Proper prop selection will have the engine within 150 RPM's of the maximum RPM number, when normally loaded. This is especially important in boats that demand a high level (and consistency) of performance.

[Phoenix 5]

I still have seen anyone address the root issue of the 5750 rpm wall. The props I have tried should have a 300-500 rpm range between with a 23 tempest on the low side and a 24p fury 3 blade on the stiffer side. Will little to no change maybe 100 rpms being generous. As stated early I have had throttle demand check a 2 different dealers both show a 100 %. Also took any slack up in the hot foot cable. Also plane easy and pulls good to 5600-5700 range and just flattens out at this point.

[EuropeanAM]

Also took any slack up in the hot foot cable.

Any changes to the throttle cable AT ALL require you to have Demand Linear re-checked. Even the slightest adjustment here can adversely affect the engine's ability to reach WOT.

Respectfully: And coming from someone that's seen MANY of these- you have made only a modest prop change. 21-22P should show you what it has.

Also note: We should verify that these figures are coming from SMARTCRAFT (and not from an analog tach). Analog tachs are not really reliable for this purpose.

[Phoenix 5]

This rpms are off a merc monitor. I have always understood 1 inch of pitch is up or down is usually 150-200 rpms depending on slip. A 23p fury and the 24P fury run only 50 rpms apart.

[EuropeanAM]

While the general rule is 150-200 RPM's per pitch, that may not actually be accurate in this case.

I would look to see if you can find someone to let you TRY a 21 or 22P prop in the Tempest or Fury lines.