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spark plugs don't look awesome

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DockDoc View Drop Down
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    Posted: November-08-2020 at 10:00pm
Think I replaced these last summer... pulled them today to fog the engine for winterizing. They clearly look fouled. 

I'm thinking this is from an over-rich condition, does that seem right? 

They looked the same in all 8 cylinders. Boat was running fine all summer.

I did adjust the idle mixture this summer using a vac gauge under load, was pulling about 15 psi. 

What should I be doing next?



 
1993 Sport Nautique
PCM 351w, no ProTec
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Dreaming View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Dreaming Quote  Post ReplyReply Direct Link To This Post Posted: November-08-2020 at 11:49pm
yes, this looks rich.   Adjust your idle mixture at idle, but not under load.  You could probably lean that out a bit and get better fuel economy without adverse affects.    clean the plugs, re-adjust and then read the plugs in a couple of hours to see if you need to lean or enrich. 

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KENO View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: November-09-2020 at 7:35am
Looks to me like your choke wasn't open last time you idled the boat, maybe during your winterization .

Them plugs look "all fluffed up" with carbon from being rich.

What do you have for plugs in the engine?

It could be a really weak spark at idle, but if like you said, the boat ran good all summer.......maybe not.

Did you ever do anything with those parts under the distributor cap?

Did you ever figure out your funny transmission noise?

Questions, questions Wink
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GottaSki View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote GottaSki Quote  Post ReplyReply Direct Link To This Post Posted: November-09-2020 at 10:01am
One cannot misadjust the idle mix far enough to cause that.

like KENO sez, choke on would do that

Blown power valve would do that

wrong gasket on PV would do that

Plugged air bleed could cause that


"There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing."

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