Yami OX66 250hp problem: Missing

[5-Salt Fever]

97 Yami OX66 250hp problem: Missing

One possibly, two cylinders missing but only after running for 30-45mins or so. Lighter or heavy loads doesn't change problem - but definately an issue during extended runs of 1-3hours.

-3,800-4,300rpm Range
-Increase to full trottle and missing stops
-Missing begins as intermitant with slight increase in fuel burn - perhaps 1gal per hour addn'l.
-Over next 10-15mins missing grows to where fuel burn increases by 8-10 gals per hour to maintain same rpm.
-again...increase to full trottle and it cleans itself out and runs great.

Cleaned and re-gapped culprit plug. Checked compression noting no problems for problem cylinder. Bad Plug, wire, or coil perhaps cause by higher temp associated with longer runs. Recenlty replaced all plugs and had about 30hrs of trouble free operation. Could be oil/fuel mixture too rich at the bad cyl or.... ???

Anyone have this problem? Like get some imput before the taking to the dealer only to have them tell they can't duplicate the problem.

[mlee]

I'd clean the 02 sensor and check the throttle position sensor.

[5-Salt Fever]

mlee - 9/11/2006 8:14 PM

I'd clean the 02 sensor and check the throttle position sensor.

O2 Sensor - Spray it out with Carb cleaner I assume and re-install. Throttle Position Sensor - could use a little help with this one as I am not sure what to do here.

Thanks

[John_Madison CT]

Remove 02 sensor and the "dogbone" or tranfer tube. Soak tip of 02 sensor in Combustion cleaner overnight. The transfer tube and area around the block should be free of any carbon.

Do a search on cleaning 02 sensor as there should be plenty of posts on this topic.

[Harpoon]

Do you have ETOH in your gas out there ?


Ethanol/Water can cause all sorts of strange/intermittant problems. If you haven't already done it, replace your 3 low pressure/diaphram fuel pumps and clean the screen in your high pressure pump.

the new oring is 35.00 the pumps are about 35.00 each.

The switch to the yammie 10 micron fuel filter separator. It is all simple stuff.

[DreamWeaver21]

Would definately try cleaning the O2 sensor. Does it surge? I have a 97 that surged and dropped a cylinder or two and changing the O2 sensor fixed it. Mine however was messing up at WOT too.

[seahorse]

Here is an article that may shed some light on the O2 sensor and how to clean and test it

boatsetup.com/O2sensor.pdf

[5-Salt Fever]

DreamWeaver21,

No surge just missing but I am with you on the O2 sensor as definate possible source of my problem.

Have the sensor soaking in combustion cleaner as we speak. The tube was fairly clean on the inside but the outer surface was really clogged up - I am hoping the 3mm's of carbon deposits could be acting as an insulator cause higher the actual temps at the sensor. The sensor itself wasn't particularly dirty however - fingers crossed that a good cleaning will get it done.

[5-Salt Fever]

seahorse - 9/12/2006 5:36 PM

Here is an article that may shed some light on the O2 sensor and how to clean and test it

boatsetup.com/O2sensor.pdf

Great Article - thanks Seahorse.

[Tower Todd]

5 Salt,

Glad you found your way to this site. Good Luck,
Tower Todd

[JUSTINTIME]

check ur pulser outputs

sounds like when u warm things up it happends, so something under ur flywheel is the problem

try taking a heatgun/blow dryer and warming the startor/pulsers up while the engine is cold and see if this is the problem