2003 yamaha sx250 ox66 misfire

[xltier]

Having some trouble with my 2003 250 2 stroke today.when its idling after a minute it will cough real hard and STOP the motor.It will restart instantly.then idle for a couple minutes and again it might sputter but usually it just shakes and stalls.almost sounds like a misfire when it does it.dont seem to bother ov er 2,000 rpm.i replaced all filters including injectors.no help.

 

[xltier]

thought I would add that I took the 02 sensor out for testing and there was some oily grit stuff in there.shouldnt that be clean and dry.

 

[inthwtr]

I have had this exact same issue on my 2000 OX66 225. New plugs, new pumps.

 

[xltier]

I did new low pressure pumps and sparkys.vst filter-low pressure filter-injector screens.

 

[xltier]

I did new low pressure pumps and sparkys.vst filter-low pressure filter-injector screens.

when it does the cough thing idling in neutral on a hose in a barrel of water,, it will throw water out of the barrel. enough to soak your pant leg.(lol)

 

[99yam40]

sounds like a lean sneeze

 

[xltier]

any thoughts? I have replaced all filters and had a pressure gauge on the test port at 38lbs when it was doing it.replaced injector inlet screens also.i9 pulled the injector rail today and zip tied the injectors to the rail and spun the motor.they all appeared to be spraying equal.i am at a loss.i sold a great running islander with a mercruiser that I work on all day and bought something that isn't right that I don't know anything about. wow I have a screw loose. lol

 

[xltier]

I don't think it is lean because it sucked down about 2 quarts of gas and sea foam mixture in about 60 seconds.