2000 VX225 OX66 Smoking at Higher RPM???

[sarmst100]

The other day I slowed down in a congested area and happened to look back and I had a trail of smoke behind me and bellowing out of the water. Motor seemed to be running fine before this. Not sure how long it has been smoking like this. I was probably running 3500-4000 rpms at the time. I shut it down and haven't run it anymore.

The gap at the oil pump is 0.015 with the throttle linkages disconnect but it seems to be burning more oil than it should. I've gone thru 2 gallons faster than usual I think.

The O2 sensor was cleaned last year and I run Seafoam and StarTron religiously. Will a faulty or dirty O2 sensor cause this? Diaphams were changed last year also but that doesn't mean one isn't bad either. Warning buzzer is working when the kill switch is pulled. I did a compression check and within 5 psi over all cylinders with it cold.

Any ideas where to start? Could the seals (o-rings) at the back of the oil pump be bad allowing oil directly into the block? If so will I need to purge the oil system after reassembly?

 

[rodbolt]

Re: 2000 VX225 OX66 Smoking at Higher RPM???

diaphrams are easy to check, O2 sensor output is easy to test.
yes the oil pump shaft seal can leak but its simple to change and no purging nessasary.

 

[sarmst100]

Re: 2000 VX225 OX66 Smoking at Higher RPM???

Thanks rodbolt for your reply. I will check the diaphams this weekend and test the sensor again. Tested it last year and it was fine then. Went ahead and ordered the seals for the oil pump also.

Have you ever seen a fouled 02 sensor or bad diaphams cause smoking as I described? I was running around 30 mph I would guess and leaving a heavy trail.

 

[rodbolt]

Re: 2000 VX225 OX66 Smoking at Higher RPM???

yep
I have also seen the oil link at the pump break and do the same thing.

 

[sarmst100]

Re: 2000 VX225 OX66 Smoking at Higher RPM???

Well I fixed the smoking. I installed a new NTK 21006 O2 sensor, new plugs, and changed out the o-rings on the back of the oil pump. Took it to the river today and it belched out a big puff of smoke as I took off but quickly cleared up. Very little smoke at an idle also. Seems to have more power also. I believe it was the o2 sensor. It was a jet black but not oily. The oil pump o-rings didn't look bad. Plugs looked normal.

Hope this will help someone out in the future.

 

[rodbolt]

Re: 2000 VX225 OX66 Smoking at Higher RPM???

myself I would have tested the O2 sensor output voltage before replacing it,I also test it after replacing to insure its working.
a faulty O2 sensor can and will burn a piston above 4000 RPM.

 

[sarmst100]

Re: 2000 VX225 OX66 Smoking at Higher RPM???

I plan on testing it next time out. Quick trip after work and the ramp was a little busy. The old sensor was replaced in 2003 so figured it was good to replace it. It tested good last year when I cleaned it.

 

[TomS]

Re: 2000 VX225 OX66 Smoking at Higher RPM???

I looked up that O2 sensor, and its only like $40.. will that work as well as the $300 Yamaha one?

Rodbolt, is there any way to test/inspect the oil pump diaphragms?

Thanks,

-- Tom

 

[sarmst100]

Re: 2000 VX225 OX66 Smoking at Higher RPM???

I have read where others have used the NTK and it "seemed" to work fine. The old one has NTK stamped on it.

 

[rodbolt]

Re: 2000 VX225 OX66 Smoking at Higher RPM???

dudes
I am a yamaha tech working for a yamaha dealership.
dont ask me what aftermarket stuff will work.
all I can say is there are only so many ways to build a 4 wire heated O2 sensor.
as long as the sensor output voltage is correct by the 3 bullitens,disregaurd the flame test one, it should work.
as far as testing pump diaphrams,use a vacum tester,install bolts and nuts in place of the hold down screws and see waht happens.
plug the intake,apply vacum on the outlet, if it holds at least the diaphrams are not ruptured.
can still be stretched and not work but not ruptured.

 

[jetrink52]

Re: 2000 VX225 OX66 Smoking at Higher RPM???

sarmst100 check your PMs please.

 

[SBH2OMan]

Re: 2000 VX225 OX66 Smoking at Higher RPM???

Well I fixed the smoking. I installed a new NTK 21006 O2 sensor, new plugs, and changed out the o-rings on the back of the oil pump. Took it to the river today and it belched out a big puff of smoke as I took off but quickly cleared up. Very little smoke at an idle also. Seems to have more power also. I believe it was the o2 sensor. It was a jet black but not oily. The oil pump o-rings didn't look bad. Plugs looked normal.

Hope this will help someone out in the future.

Hey, hope you are still monitoring this channel... Are you saying that just changing out the O2 sensor solved your over-oiling problem? Or did you find a leak in one of the seals on the oil pump, etc.? I'm having similar issues with over-oiling and have tested my O2 sensor and it seems to be functioning properly but it is not right exactly inside the specs all the time (it runs up to like .8 and .9 while operating at high RPMS then comes down around .3 and .4 at lower RPMs). I have triple-checked my oil control arm, and it is adjusted properly (though there seems to be a lot of slop in the upper black arm that it attaches to).

Thanks for the tip on the NTK unit. I was staring at O2 sensors recently and came across that one and was convinced it might work. You just confirmed it for me.

 

[jeffersondodson561]

Re: 2000 VX225 OX66 Smoking at Higher RPM???

Are you saying that just changing out the O2 sensor solved your over-oiling problem? Or did you find a leak in one of the seals on the oil pump, etc.?

The only factors that determine your oil consumption are rpm and throttle angle under normal conditions. You could have a faulty seal. I think he threw everything but the kitchen sink at it. The O2 sensor only makes adjustments in the upper rpm range of the motors fuel/air calibrations.

 

[SBH2OMan]

Re: 2000 VX225 OX66 Smoking at Higher RPM???

The only factors that determine your oil consumption are rpm and throttle angle under normal conditions. You could have a faulty seal. I think he threw everything but the kitchen sink at it. The O2 sensor only makes adjustments in the upper rpm range of the motors fuel/air calibrations.

Yea, that's my understanding and why I was curious. I'm beating my head against a wall (or a dock, take your pick) to try and figure out why I'm burning so much oil and fouling my O2 sensor. Sounds like I need to do a pump output test and check for leaky seals...

 

[jeffersondodson561]

Re: 2000 VX225 OX66 Smoking at Higher RPM???

Have you noticed an increase in oil consumption? I would just go ahead and purchase the seals and replace them.