Re: 1986 mercury carbon on plug
Its possible the bottom coil is weak, change it with another and see if the problem moves.<br /><br />If it was a rich condition..we should see it with both the bottom cyl,s.<br /><br />If it was a lean condition..we would see a white spark plug on both bottom cyl's<br /><br />Therefore I would lean more towards an electronic part giving you grief.<br /><br />OR <br /><br />Check the bleed hose..maybe it is not on or has a hole in it. They are the tiny hoses that bleed off excess fuel.<br /><br />TMD
