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wake309

cylinder #8 not firing

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wake309

i just changed my plugs, wires cap, and rotor on my 02 wakesette (350 carb). i noticed that #8 was oily, hoped it was due to bad wire. i am worried that i my have burnt a valve. #8 has spark. what do you all think? i cant stop thinking about it.

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68Slalom
i just changed my plugs, wires cap, and rotor on my 02 wakesette (350 carb). i noticed that #8 was oily, hoped it was due to bad wire. i am worried that i my have burnt a valve. #8 has spark. what do you all think? i cant stop thinking about it.

Check your compression!

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D-GOOSE

Did you have a miss fire or rough running motor before finding the oil plug.

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radioman

like the goose said we need to know if your engine has a miss ie shakes under a load, runs rough.

oil on the plug would not be a burnt valve, oil on the plug could just be a vavle stem seal. if someone knows what they are doing and has the air hose gixmo they can be change pretty easy. without removing the cyl head.

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wake309

harder starting, a little smokey, and less power at the end of last season. i know that water line going to the trans cooler was partially blocked for who knows how long, she never went above 160 though. i am hoping that the low volume of water making its way to back of the motor didnt cook something. she is missing, #8 is not firing

Edited by wake309

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footnlongline
harder starting, a little smokey, and less power at the end of last season. i know that water line going to the trans cooler was partially blocked for who knows how long, she never went above 160 though. i am hoping that the low volume of water making its way to back of the motor didnt cook something. she is missing, #8 is not firing

After the new plug. is it still not firing? If its blow by it should run ok until the new plug becomes oil fouled. check to see if you are getting spark on that plug. How many hours?

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wake309

its got spark and 145 hrs. on the motor. there was also a tiny bit of oil coming from between the head and exhaust manifold at #8.

Edited by wake309

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footnlongline
its got spark and 145 hrs. on the motor. there was also a tiny bit of oil coming from between the head and exhaust manifold at #8.

That motor has very low Hrs for that kind of trouble. Did you winterize it or have it done by someone else? Freeze damage may not be out of the realm of possibilities. Sound like trouble though, I would do a compression test next.

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vette-ski

Sounds like the problems started last year so I doubt it's from a winterization gone bad. Are you sure it's oil and not fuel on the plug? Oil would be either from rings or valve seal. I wouldn't think that a little seepage from either of these two sources is enough to kill a cylinder. If you put a new plug in it SHOULD run ok until it gets fouled. But if you keep the plug hot it should burn off any residual oil that gets on it, keeping it from getting fouled. So either it's a LOT of oil or something else. Like other's, compression is easy to check and your next step in diagnosis. That will rule out the leaks you suspect. Are you using the correct heat range plug like stock?

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D-GOOSE

Oil on the plug can come from valve steam seal going bad (but not likely because its only going to be a little bit) or the rings that are not seating.

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radioman

you must have an INTAKE push rod off and or a broken rocker arm on #8. If the intake does not open the extreme high vac in the cyl pulls the oil bye the rings.

remove vavle cover for an easy inspection.

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wake309

i am using the right plugs, valve seal seepage would burn off, and there no chance of freeze damage. its got spark so i just keep thinking the worst. i am gonna do a leak down test next time i go out to the river (parker, az where the boat stays).

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footnlongline
i am using the right plugs, valve seal seepage would burn off, and there no chance of freeze damage. its got spark so i just keep thinking the worst. i am gonna do a leak down test next time i go out to the river (parker, az where the boat stays).

I'm not quite sure what the terms of the warranty are, but with only 145 hours and a proper maintenance log you might be able to negotiate help from the manufacturer, I think it would be well worth a try. Did you ever over heat it?

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wake309

the boats is an 02 so i think the warranty is long gone. she got hot one time, i shut her down as soon as needle began to go up. it was also within 5 minitues of launching.

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Sunsetter

FWIW I had about the same symptoms last year- one cylinder not firing- heard motor change sound at high rpms while barefooting- thought it was a plug fouling out- changed plug next day, it was fouled- no change in motor performance- looked at distributor cap and rotor- looked bad so changed those- also made no change- had some good spark plug wires lying around so changed that spark plug wire- no change- finally did a compression check and found zero psi took head off and took to valve shop and they said it was "valve recesstion" basically where the valve gets pulled up so hard it deforms enough where it will no longer seal- they said it was not uncommon on that genaration truck/boat motors - the cylmer manual I bought to remove/install the heads mentioned it- The shop replaced all the valves with a slightly harder valve that should not deform. No troubles since then- my boat is a 2002 sunsetter- 310hp carb motor- had about 600 hours -now about 650hours as others have said your next step should be a compression check- and then go from there.

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wake309

i did a leak down test and compression test, everything was perfect. i checked the undr the cap again and decided clean the pick up coil with contact cleaner. she fired right just fine. took the boat out ran good until the end of the day and then she started missing again. to make a long story short the carb was dumping tons of fuel, that was the problem all along. to much gas drownding out the #8 and #7 cylinders.

Edited by wake309

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vette-ski

Good to hear it's nothing major and you found it before tearing the motor apart.

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D-GOOSE
i just changed my plugs, wires cap, and rotor on my 02 wakesette (350 carb). i noticed that #8 was oily, hoped it was due to bad wire. i am worried that i my have burnt a valve. #8 has spark. what do you all think? i cant stop thinking about it.

Would not have figured a rich carb would make a pulg oily. Glad you figured it out.

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68Slalom
i just changed my plugs, wires cap, and rotor on my 02 wakesette (350 carb). i noticed that #8 was oily, hoped it was due to bad wire. i am worried that i my have burnt a valve. #8 has spark. what do you all think? i cant stop thinking about it.

Would not have figured a rich carb would make a pulg oily. Glad you figured it out.

I agree, running so rich that the plug looks oily would worry me. I would think that it was low spark not so much extra fuel, it's a good thing that the rings were not washed out from the fuel. I've seen that happen a lot, when I was building engines for a living. Glad it all worked out for you Thumbup.gif

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