Rebuilt carbs, new o rings, mixture screws etc..bench set butterflies and mixture screws.
Put the carbs back on, starts ok with no choke, did carb balance, all good...sounds a lot better,and goes better now, but stuttery at low end.
Took plugs out and 1,2,3 nice colour, but 4 has oil (not petrol) on electrode..
Checked the coils, coil leads and caps,swapped with some spares still the same result, oil on number 4 plug.
Any ideas, carbs again, or am I looking at valve seals ??
Cheers