My name is Randy. I have a 2008 Mercury, 50 hp, 2 cycle outboard on a pontoon. While cruising along at 3,000 rpm, the motor will at times (not always) drop to 2,000 rpm. Within a short time it will resume to the 3,000 rpm. The gas is fresh and the filters have been replaced. It feels like the engine is going to die but it doesn't. any suggestions?