2001 Mercruiser 5.7 EFI No WOT Under Load

[phillyboater290]

Looking for guidance. I have twin Merc 5.7 EFIs on a 2001 Sea Ray Amberjack 290, Bravo Sterndrives. When cruising, I cannot get the Port engine over 2300/2400 RPM even at Wide Open Throttle, and I need to hit 3000 to get on plane. Observations:

1) low water flow from port engine when running. When compared to stbd, the port has noticeably less bubbling and turbulence compared to the stbd engine.

2) port engine is noisy up to about 2300/2400 RPM, then quiets down once over that hump. Under no load/neutral, I have no problem getting engine up to 3000rpm+ - when cruising I can’t get above 2300/2400 rpm.

3) had a very high (360ppm) CO reading in the cabin when operating this weekend (CO alarm went off, cabin door was open while underway)

4) Noticeable and unusually strong fuel smell when operating - was not happening last year.

5) water temp runs hotter on the port engine than on stbd at similar RPMs

What I’ve done:
a) attached code reader to engine - no codes
b) revved port engine under no load - no issues
c) mechanic replaced impellers less than a month ago

Link to videos of tests and performance: https://1drv.ms/f/s!Au-wPZ0_2wZKgP9Ia38NtJm0pYGYaw (18 photos/videos are uploading, so this may take an hour or two to update.)

Looking for ideas on what to do next. Thanks everyone!

 

[alldodge]

The folder is empty
Do a compression test

 

[phillyboater290]

The folder is empty
Do a compression test

Thank you, folder should have files now.

I will read up on compression tests - what will that test tell me? If there is a leak in the exhaust system or manifold?

Is there a way to test for obstructions/restrictions in the exhaust system?

 

[alldodge]

Compression tells if the motor is healthy. New motor should be 150 psi, as it wears it can get lower. The lower pressure gets the less HP the motor has. Test will not show if there is a clogged exhaust

You mentioned one motor gets warmer then the other which can mean it has a blown head gasket