250 OX66 Sluggish w/ high fuel burn per hr

2002 LX250TXRA EFI 197 hours

Recent Maintenance: new o2 Sensor, new Plugs, new VST Filter

I usually run around between 4200 & 4400 rpms while burning around 12GPH on Navman.

This Sunday I noticed the GPH ran up to 20+ and at the same time the engine sounded sluggish while the RPMs remained around the same 4400. I gave it more throttle at one point and it kind of broke free and ran fine.

Any ideas?

[jb123]

possibly lp fuel pump....do you see much unspent fuel out of exhaust ?

I didn't notice any gas in the water...

[jb123]

were you LOOKING at the water....you wont see MUCH but there will be signs of gas with a bad lp pump.

check compression

with motor running about 1200 on the hose, pull each plug wire at a time, ensuring sound/rpm change.....ensuring all are firing.

you can also unhook each injector at a time...listening for the same.

my 200's at higher rpms will burn around 21-22 each so maybe your navman is off a bit... the 250's have a much larger bore.

Low Pressure Pump Changed

I changed all three LP Fuel Pumps, New Primer Bulb, Checked Fuel Intake from tank to Filter(no obstructions), New Fuel Filter....

SAME PROBLEM.....Please help

[jb123]

i would try using an auxillary tank, with different hose and ball, hooked to the motor filter.....to isolate motor from fuel supply.

did you pull plug wires to see if one cyl isnt firing?

also if your HP pump hasnt had its filter cleaned in a year or so...do it.

[jb123]

also....you changed out the sensor...but you may want to test it also :

http://www.boatsetup.com/O2sensor.pdf