225 pro xs Questions

[Phoenix 5]

Serial number3B138377 proxs 225 I have couple of questions. First, recommend wot is 5600-6200 as long as I am in this range are my rpms okay? I have tried a range of props from 23-25 pitch in furys and tempest. If I understand right after 25+ years of running 65-80 mph boats there should be a 150-200 rpms difference between pitches roughly depending on slip percentage. Question Why will my motor turn within 100 rpms no matter the prop? For example a 23 tempest verse a 24 fury is equal to 1.5 inch of pitch the tempest turns 5850 all the winter or summer and my 24 fury turns 5770 winter or summer. These are merc monitor rpms. I have had my hot cable check and my throttle demand checked twice both showing 100 percent. It is like some kind of wall at 5700-5850 my motor just quits pulling kind of like a some limiter. There is no reason with my boat and load I should need less than a 23 p prop. I have a hydraulic jack plate and I have been up to the point of losing h2o pressure with no noticeable rpms gain. I know a couple of guys with very close to the same rig with a 200 4 stroke that will run with in 1 mph of my 225. By the numbers I would need a 21p prop to get to 6200 rpm and that's just wrong. This motor is on a 919 phoenix with a 10 atlas hydraulic plate. The boat lifts good so its hull drag. Any help would be greatly appreciated.

[mactlman]

The smaller throttlebody on the 225 is choking engine down at the upper RPM range. Courtesy of mercury engineers

[EuropeanAM]

Serial number3B138377 proxs 225 I have couple of questions. First, recommend wot is 5600-6200 as long as I am in this range are my rpms okay? I have tried a range of props from 23-25 pitch in furys and tempest. If I understand right after 25+ years of running 65-80 mph boats there should be a 150-200 rpms difference between pitches roughly depending on slip percentage. Question Why will my motor turn within 100 rpms no matter the prop? For example a 23 tempest verse a 24 fury is equal to 1.5 inch of pitch the tempest turns 5850 all the winter or summer and my 24 fury turns 5770 winter or summer. These are merc monitor rpms. I have had my hot cable check and my throttle demand checked twice both showing 100 percent. It is like some kind of wall at 5700-5850 my motor just quits pulling kind of like a some limiter. There is no reason with my boat and load I should need less than a 23 p prop. I have a hydraulic jack plate and I have been up to the point of losing h2o pressure with no noticeable rpms gain. I know a couple of guys with very close to the same rig with a 200 4 stroke that will run with in 1 mph of my 225. By the numbers I would need a 21p prop to get to 6200 rpm and that's just wrong. This motor is on a 919 phoenix with a 10 atlas hydraulic plate. The boat lifts good so its hull drag. Any help would be greatly appreciated.

1. Triple check Demand Linear. If it's not achieving 100% Demand Linear, it's not going to make the difference you expect when changing props. ESPECIALLY true if Demand Linear is below approximately 92%.

2. 21-22P is not out of the question on one of those boats. We have a number of the 21' w/250's that are running 23P or 24P.

[Phoenix 5]

I will have it check a 3rd time. If it check out okay then what? I talked to my dealer and the folks at phoenix. They both say that most people with my setup is running a 23or 24 fury or tempest and are running 74-76 at over 6000 rpms. That being said if I drop to a 21-22 and turn 6000+ rpms and run 68-70 mph I have not achieved anything positive. Something is just not adding up.

[Phoenix 5]

I believe you are correct. Restrictor plate basically. It's air or fuel through or timing through the ecu . It runs like a striped ape from hole shot to 5400 then the 300-450 rpms are slow to gain.

[bassfisher444]

Do you have lithium batteries in the rear and a bunch of electronics on the bow? That will slow you down as well.

[mactlman]

I believe you are correct. Restrictor plate basically. It's air or fuel through or timing through the ecu . It runs like a striped ape from hole shot to 5400 then the 300-450 rpms are slow to gain.

mine stops at 5800 every time with a 23 fury3--plate height doesn't change it--many phoenix guys are have the same issues --all 200-225hp boats are also

[Phoenix 5]

If it only turns 5700-5800 rpms no matter the prop. I think run as big a prop as you can plane off comfortably and get the most speed and mileage you can. Mercury needs to address this issue. I could have bought 200 and saved money for the performance I am getting.

[EuropeanAM]

Jeremy- it looks like you've been running this boat for 2 years now, a little over 100 hours?

Has the boat EVER performed better/properly? Spark Plugs and Plug Wires tested/inspected?

See if you can FIND a 22P you can stick on it. Really need back-to-back max RPM figures with performance info for the current prop, and the 22P Prop.

Basically looking to confirm we CAN spin the engine up into the top of the Power Band.

[Phoenix 5]

It has run this way since breaking in the motor. Just replaced the plugs myself. I also had my dealer replaced my wires and a o2 sensor after a 6 beep fault at the 104 hour mark. This helped the bottom end a little no improvement to the top end at all.