Had my 115 Mercury out today fishing for the first time this season. Started right up and I let it idle while parking the truck and trailer. Ran fine to my fishing spot. Got full speed but I only ran it a short distance. When in for lunch and again the motor ran fine. Again just a short distance maybe an 1/8 of mile. Ate and headed back out was running full throtle and all of a sudden it lost power and was hitting on 2 or 3 cylinders. Idled fine. Got it on the trailer and check the plugs and all were black and greasy. Put in new plugs and it seemed to go to 5000 rpm on the tach but still has a little miss. The gas is from last year. Any ideas what is going on? Motor has never given me any problems.
