I just recently purchased a boat with a Merc 115 Saltwater 2 stroke. I had a leaking head gaskett which was fixed professionaly. The boat ran great for 3 trips totaling 6 running hours. On my last trip I was running just over a quarter tank of fuel and I was trolling at low RPMS for about 20 minutes. I trottled up, as the boat came up on plane and settled I heard what sounded like a ticking / chatter noise coming from the engine. As I throttled down she was running very rough and bogging a bit. I had a 40 minute trip back into the dock through a few no wake zones and at low RPM's the engine wanted to stall. I tried trottling up again and she did run a little rough. Low RPM's she rean ver rough and wanted to stall again. At the dock she did stall. I had to let her sit pump the baulb and raise up the Idle just a bit to get her on the trailer. When I got the boat home I ran her with the muffs and she started and ran without stalling. I check the pluggs and the number 1 plug appeared dry and the rest were wet.They were in good shape. Can anyone share what I may be up against. The motor has not seen saltwater prior to my purchase and I may have put a good 40 hours on her prior to having these problems.<br /><br />Any direction would be greatly appreciated.<br /><br />David 