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Hi everybody! I have a 1979 Mercury 140 hp inline 6 cylinder outboard motor. Hard starting, doesn't run on all six. #6 cyl plug looks almost new whereas 1 through 5 are black from fouling. #6 plug is wet with no signs of fouling or running tan or white. 1st I checked compression and all cylinders are between 128 and 135 psi. Checked spark of plug on different coil and plug has good spark, checked spark on # 6 coil and has good spark. There are 6 cyl with only 3 carbs. I have ran at full throttle and can get 42 mph out of it but with the visual condition of the plug it does not seem to be firing on # 6. It always has a lag in mid range until it warms up for many minutes. Could reed valves be the culprit?