920 Pro Xp/250 Merc Pro XS drastic speed loss. Need help or advice or both!

[SmokyMtnBassin]

Guys/Gals,

I have been reluctant to post my issue, but I have tried everything I know to try and can't find a solution. Maybe some of you can help me.

2016 920 Pro Xp
2016 Merc 250 Pro XS
25 Fury

First off my boat would run 73 or 74 with me by myself and I have gps'd it on the James River with a partner at 76.5
This was with the factory jp at the factory settings. Trim on the first "small" mark. If I trimmed up anymore it would lose speed and get crazy. I lost speed and tried a 26 fury. That day speed didn't improve and it blew compressor. Dealer installed new compressor, no improvement. Sent my prop to have it reworked, no improvement. Installed a 10 Atlas hydro, no improvement. Lost a powerhead, fuel rails and all. All just replaced 2 weeks ago, no improvement. I just borrowed my buddies 25 fury off his 721 that runs 74 with him and his partner on the same lake. Best I could get this morning was right at 70 and it was screaming, almost 6k rpms. Came down off pad and lost another compressor. I have no clue what the issue is. It doesn't matter what my jp height is and where my trim is. At 5800 rpms it hits a wall with me and a partner at 66.7 mph. I have adjusted trim, height, both constantly trying to get it to run what it did when I first got it. I'm at a loss what it can be. The BEST I can get by myself no matter fuel weight is 70 and that is turning it way closer to 6000 rpms than I want. I have tried a 26 fury, 26 tempest and multiple 25 furies off of my buddies phoenixes with absolutely no improvement. If I trim it down to where it should want to run and go up and down on the jp the rpms either skyrocket with no improvement in speed or drop with no improvement on speed. Any suggestions would be greatly appreciated. I know that sounds crazy, but its the best way I can explain it.

Thanks,
Smoky

[kry29]

Sounds like it's a motor issue. That's the only thing that's changed. I've always read the injectors and rails need to be cleaned after a compressor failure also. On the rpms, is that a merc monitor or factory gauge? The factory gauge can be off

[Phoenix Jim]

You need to post this in mercury forum as well. There are some experts over there especially Don weed

[Wackyjig]

Hotfoot cable could have stretched, came loose, or something along those lines to cause the speed loss. As far as blowing compressors and then a powerhead after repair, mercs do that.

[GBhoss]

As far as blowing compressors and then a powerhead after repair, mercs do that.

Mercs that are not repaired correctly (not cleaning the rails, injectors and the lines) will blow a powerhead because there is junk from the compressor inside the motor. Having blown a second compressor means you have a serious motor problem. Head over to the Mercury forum and let Don or Savage help you out.

[rammerjammer]

Sounds like a continued problem in the oil return lines, direct injectors/rails. I assume you live in western NC which is within an hour or two of one of the best Mercury mechanics around in Don Weed @ European Marine. Take your investment to him and let him fix it right the first time.

[kry29]

Sounds like a continued problem in the oil return lines, direct injectors/rails. I assume you live in western NC which is within an hour or two of one of the best Mercury mechanics around in Don Weed @ European Marine. Take your investment to him and let him fix it right the first time.

+1.

[GBhoss]

Sounds like a continued problem in the oil return lines, direct injectors/rails. I assume you live in western NC which is within an hour or two of one of the best Mercury mechanics around in Don Weed @ European Marine. Take your investment to him and let him fix it right the first time.

This IS the guy you want to work on your motor.