Mercury Repair Questions? Ask a Mechanic for Answers ASAP
Hello, so when you changed the spark plug you found one covered in oil, and you are having trouble with a misfire?
Ok well the short answer is yes that could cause a misfire. But the real issue is why is there oil on the spark plug. Have you replaced anything else to try to fix the misfire?
Oh ok, its either the oil rings on the pistons are going bad and not holding oil below the compression chamber, or there is an oil leak from the head gasket into the cylinder. To find out which you'll need to perform a leak down test with a leak down tester.
Well the spark plugs go directly into the cylinder head, and they do not go through the valve cover. Was the oil on the top of them or on the threaded end?
If it is just a valve cover leaking into the spark plug hole then no the engine will not have to be removed
Oh ok, well yes then it is probably the valve covers leaking.
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