2000 250hp OX66 shuts down at high RPMs

[Capt Picon]

over the years I have personally ran enough 250 OX66 motors to tell you at or near WOT it consumes 25-29 GPH. it how they work. 2 or 4 stroke.
last summer I took a boat out with triple 350's, at 5400 the flow was 94 GPH.

I will double check on that, maybe the check valve on the gas tank is restricting the flow? The paper filter in the motor is always full of fuel, even when the shut down happens. Primer bulb is not collapse and it gets hard if I pump...That's why I ruled out flow restriction.

Im planning on re-check the VST today..

What about the vst pressure regulator....I cleaned the screen, but is there a way to test?

[rodbolt17]

easy to test the regulator, install the test guage and watch it.
typically when the regulator filter clogs it make them run very rich at idle,not so bad when WOT but if it clogged so bad as to cause a shutdown you would not restart it. would be severly flooded.

typically when up and running that filter cup should be about 1/2 full.
if you still have the little check valve between the cup and the lower lift pump.
remove it,unthread it, dump out the guts and install just the valve body back in the line.

[Capt Picon]

easy to test the regulator, install the test guage and watch it.
typically when the regulator filter clogs it make them run very rich at idle,not so bad when WOT but if it clogged so bad as to cause a shutdown you would not restart it. would be severly flooded.

typically when up and running that filter cup should be about 1/2 full.
if you still have the little check valve between the cup and the lower lift pump.
remove it,unthread it, dump out the guts and install just the valve body back in the line.

Ok went and check all my fuel lines for restrictions...from the low pressure pump-motor paper filter-primer bulb-flow meter-water/fuel filter separator filter all fine.

Then I check from Water/fuel filter to the gas pick up tube...bingo!. Pick up tube and check valve (inside facing pick tube) was clogged with alluminum shavings and what it look like insect parts !!! All that stuff was packed between the check valve and top part of the pick up tube.

I went ahead and removed the check valve fitting and replaced with a regular fitting...hopefully and can catch everything else on the fuel/water filter.

I'll test ride tomorrow and check for the fuel flow !!!

Any suggestions?

Thanks.

[Capt Picon]

PROBLEM SOLVED!!

All that garbage was obstructing the fuel flow. Now, when I hit 5500-5700 rmps my flow meter shows 25-27 gph !! Pretty thristy ouch. But the power is there!! Boat ran beautifull!!

Should I switch to a 17 Pitched prop, or should I stay on 15p? The full throttle operating range should be 4500-5500 rpm and Im hitting 5700 at WOT!

thanks for all the help !!

[boscoe99]

Glad you found your problem.

Now if you had had a vacuum gauge installed on the outlet of your Racor filter assembly you would have noted the restriction to fuel flow long before it caused a problem.

[99yam40]

PROBLEM SOLVED!!

All that garbage was obstructing the fuel flow. Now, when I hit 5500-5700 rmps my flow meter shows 25-27 gph !! Pretty thristy ouch. But the power is there!! Boat ran beautifull!!

Should I switch to a 17 Pitched prop, or should I stay on 15p? The full throttle operating range should be 4500-5500 rpm and Im hitting 5700 at WOT!

thanks for all the help !!

Does it hit 5700 with it loaded the way you normally run it?

[Capt Picon]

Does it hit 5700 with it loaded the way you normally run it?

You are right, I haven't run a normal trip yet. I was thinking the same thing. Plus is missing the T Top, console windshield, cooler, ice, ect!!! I'll stick with the 15p for now.

Thanks

[99yam40]

Yep ,you throw a few more people and all of the other stuff it will load up more