I recently bought a new to me 2006 Merc 115 EFI....very low hours. When I tested it on the previous owners boat it ran well..I noticed at the time that the motor was warm and assumed he had already had it out for a run. Anyway now I have tested it on my boat and have a problem. The motor starts well but before the boat gets up on plane, around 2800-3000rpm - it misses on one cylinder and I have to back off the throttle a bit. After a few times of doing this it finally runs properly and have no problems the rest of the day. I recall the previous owners mentioning that he had replaced a couple of injectors on it and in hindsight I think that is odd for a motor with so few hours on it. My best quess is that its either another injector crapping out or plugs...Anyone have any suggestions?