Yamaha OX66 carbon build-up prevention

[goose70]

Last year I used ringfree fuel addative to prevent carbon build-up (esp. around the O2 sensor). That worked so-so; the O2 sensor still had a fair amount of carbon after 150 hours that season.

This year, due to using E-10 fuel, I use Star-Tron fuel additive religiously, primarily to guard against fuel phase seperation, but I the label claims that it also reduces cardon build-up in the motor and helps clean injectors. As a result, I have not used ringfree or added a periodic injector cleaner for fear of having too many additives in the fuel and thereby throwing the hyper-sensative O2 sensor out of whack.

Do any of you have thoughts on this? Should I be using both rinfree and Star-tron? Should I also use Sea Foam occassionally to really blast any carbon buildup, or will that harm the O2 sensor?

Thanks.

[Scoutin 4 Goodies]

Bump of a good question.

Experts?

[flukin nuts]

Yamaha recomends checking and cleaning the O2 and transfer tube every 200 hrs. I do mine yearly (80-120hr). I have two of the same year engines and one has the new updated transfer tube and one does not. The one with the old stlye I have had alot of trouble with the tube clogging and causing the plugs to foul. I changed the tube and it's much better. I still clean it once a year. It only cost the price of a gasket.
I also did not run ring free and was getting a lot of carbon on my plugs. i noticed that after using ringfree they are clean.

[jevans]

You should run both RF and Startron.

[hatterasman]

i think a bottle of crown royal or 151 every once in awhile would be better and cheaper and you could also taste it to check for potency

[Megabyte]

I use Ringfree @ 1oz per 10 gals of fuel, and Sta-Bil at the rate on the label at every fill-up.
No issues these days, and my 225 OX66 runs like a champ.

It wasn't always so though. The previous owner of this boat never used any fuel additive, and it took me an entire season to get the motor cleaned out and running right.

[Special K III]

Use Seafoam shock treatment (dunk's method) to clean out the carbon build-up then use the ring-free or the star-tron to keep the carbon down. Or just do the Seafoam shock treatment every 100 hours or so.

[stripertom]

Jeff,

Maybe you can answer your own question (and one I am interested in as well) --

How has the carbon build-up been since you started using Startron and stopped using Ring Free?

-- Tom

[goose70]

Striper, that's a pretty good point (one that was too obvious for me to consider. My mechanic usually checks the O2 sensor....I'm scared to touch the thing given how sensative I keep hearing it is, but I suppose I should figure out how to check it myself. The engine was completely taken apart and cleaned over the winter (needed a rebuild), so I'm hoping that the carbon isn't too bad now. However, I do troll with it and the engine smokes a fair amount at very low speed and at start-up, and that's often a sign of a carboned-up O2 sensor (I'm told).

Someone else mentioned to me that my battery may not be sufficient for this motor, and if so, the O2 sensor will not heat-up enough to burn off the oil. I have noticed that the low-battery alarm often goes off on my electronics when I start the motor (then the battery quickly charges to 13.6-13.8), so maybe that's a problem I need to fix first. I'll be checking this weekend.

[Harpoon]

I just replaced the cylinder head on my 99 OX 66 250 as one of the plug holes was getting stripped.

I was amazed at how clean the inside of the motor was. The old head was bare aluminum on the inside. no carbon whatsoever. The pistons had nothing more than a black stain on them.

I have always used ring free. It must work.

As far as your O2 sensor, it seems like it is dependant on the amount of low rpm use. Very easy to clean though.

[solarfry]

hatterasman - 9/21/2006 7:54 PM

i think a bottle of crown royal or 151 every once in awhile would be better and cheaper and you could also taste it to check for potency

And they say it prevents carbon buildup in the arteries and helps the heart pump better.

[wetspot]

Besides running Ringfree, how are you guys cleaning the O2 Sensor? Propane torch, chemical, ...?
Thanks

[stripertom]

I have soaked in Ringfree or SeaFoam and then scraped excess carbon off with a pick or screwdriver.

-- Tom