97 ox66 225hp plug fouling

[retiredalaskan]

I have a 97 ox66 225hp that is fouling the #4 plug, i have checked the pulser coil it appears to be ok i swapped coil with another cyl. no change,the spark appears to be good when checked on the muff. but when taken out on the water and run hard it fouls out,lots of heavy black carbon on the plug. any help or ideas would be great thanks.

 

[bernieb]

Re: 97 ox66 225hp plug fouling

Hi retired Alaskan,I'm here at Cedar Key 50 miles north of you. I have read your other post and the only suggestion that I can think of is a stuck open injector,but I'm no pro. The yammy dealer at Homosassa is a 5 star rated mechanic and if you stop in and talk to David or the counter man he may offer an idea.I have a 250 yammy and trying to do my own maint.also .so let me know how things work out Berloi@aol.com

 

[rodbolt]

Re: 97 ox66 225hp plug fouling

have you checked the fuel pumps, plug cap and VST filter? <br /> poor me though I am not a five star. I have not taken the video coure to become 5 star. I have taken all the other courses and done it 30 years and the last course yamaha offers I am scheduled to take in march to get my masters cert. dont go strictly by 5 star as its just an open book video certification. watch the video´s and end in the test answers and presto your a 5 star.