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Message: <blockquote data-quote="dan filipi" data-source="post: 12939" data-attributes="member: 54">Looking at a head, oil can't run down onto the plug from a valve seal since the plug is above and to the side of the intake valve:[ATTACH=full]879[/ATTACH]I had a engine in this frame with a broken oil ring.It would smoke like a SOB for the first 5 minutes and continue to smoke lightly out the exhaust all the time.Even with that much oil the plug never fouled so I don't think your problem is oil fouling.Rule things out:Compression, GOODOil fouling, NO.Weak spark, apparently not but when you swapped coils did you also swap the plug cap and wire? What's left, has to be over rich.Too much fuel to air.Gas level in bowls is good.Needle and seat good (not leaking past).Vacuum slider moving free not being held open.Air cutoffs in good condition. (These are enricheners, if not closing could allow over rich (I think) Too high fuel pump pressure over riding needle seat.Choke plate not fully open. (?)Some restriction in air supply.Some other path which would enrichen the mixture.There is an adjustment for the accelerator pump and a check valve on number 3 carb.Could number 1 be sucking extra fuel in from the accelerator pump circuit?Sync/idle mixture screws?I had number 2 plug running sooty but not fouling. After doing a idle drop and sync it's running clean.Come on guys, what else could cause an over rich condition on one cylinder?</blockquote>