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Engine Stutter/Bog From 2k-3k RPM

F

FatPelican

New member
My 5.7 Mercruiser was "newly installed" by the owner when I bought it. The newly installed component was the Kodiak Marine 350 block, and everything else I assume was taken from his old engine. The install is very sloppy and has led me to a bunch of unrelated to this issue problems (pot puller ground disconnected, wash down pump wires corroded, engine tilt relays bad, my favorite being the complete lack of power steering pump cooler). Every since I have had it in the water, it has always had this stutter/bog from around 2-3k rpm. The engine idles fine, and after I get passed the bog, it runs great.

What I've done:

I checked my codes today using the wire and multimeter method and the only code I have is 12.

Replaced fuel filter and drained water separator.

Checked fuel pressure.

Ohmed injectors.

Replaced MAP sensor.

Tested fuel pressure regulator.

Checked timing, its close to what I think it should be. 8 BFDC if I'm correct.

Spark Arrestor is CLEAN.

Ran over 300 gallons through it, so "iTs nOt BaD gAS."

I DO NOT HAVE THE BOG PROBLEM ON THE TRAILER. ALL RPM RANGES WORK AS ADVERTISED.

Anybody have any ideas??? I've been running it and will continue run it, it would just really be nice to have that RPM range without bogging down and having the motor run like crap. I, as well as all my mechanic friends are at a loss.

Side note, what cruise RPM's should this motor be running?

93 Bayliner 2859 with a Bravo II if that matters.
 
List above doesn’t mention ignition components cap rotor wires and plugs.

Is this a newer mpi engine of older Efi engine? Engine serial number would help

If it uses TBIV ignition would replace trigger sensor In distributor
 
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