Our boat has a 2004 Merc MCM 5.0L SN CM320374. The engine had been giving us problems and progressively got worse until this weekend when it decided not to start at all.
The problem first started when trying to accelerate from stop. The engine would bog down a little and then take off and run fine. Sometimes if you came to a quick stop after running at 3,000+ RPMS it would rev back up even with the throttle in neutral. The boat began doing this more and more every time we took it out. About a week later the boat began giving me difficultly starting along with the previous problem. Sometimes once put in gear the engine would die. I put a bottle of carburetor cleaner in with the gas and the problem vanished. I thought it was solved until on the next tank of gas it came back. I tried the carb cleaner trick and this did not work. The boat would rev up fine in neutral but stall out in gear. To get back to the ramp I had to rev the motor up in neutral then put it in gear before the rpms fell below 1000. The boat stalled out whale waiting for the truck. The motor did not want to start. Sometimes it would start for a split second then backfire and die. most of the time it just would not start.
The problem first started when trying to accelerate from stop. The engine would bog down a little and then take off and run fine. Sometimes if you came to a quick stop after running at 3,000+ RPMS it would rev back up even with the throttle in neutral. The boat began doing this more and more every time we took it out. About a week later the boat began giving me difficultly starting along with the previous problem. Sometimes once put in gear the engine would die. I put a bottle of carburetor cleaner in with the gas and the problem vanished. I thought it was solved until on the next tank of gas it came back. I tried the carb cleaner trick and this did not work. The boat would rev up fine in neutral but stall out in gear. To get back to the ramp I had to rev the motor up in neutral then put it in gear before the rpms fell below 1000. The boat stalled out whale waiting for the truck. The motor did not want to start. Sometimes it would start for a split second then backfire and die. most of the time it just would not start.
