Hey all ,my 69 Evinrude sportwin doesn't run correctly, replaced,coils, points, condensers, wires,head gasket, plugs, carburetor cleaned rebuilt,water pump,it will not idle properly,sneezes/puddering,no adjustment to the low speed needle makes any difference,I'm completely stumped,could the base gasket be leaking and cause that?or a leaky intake gasket,the upper crankcase seal doesn't leak,I checked it, noticed the bottom plug is black,the top plug is relativity normal looking,any advice would be awesome!