I recently purchased a 19ft Bowrider with a 91 OMC Cobra v6 I/O in it. I have been trolling on lakes at about 2.5 - 3mph for a half an hour to an hour at a time. The engine is really bogged down and has a hard time planing out and getting up to normal speed after trolling. I just replaced the plugs and check the wires and dist cap. The fuel filter was just replaced this year. After a while of riding eventually the motor returns to normal, is there any long term damage that can occur from driving real slow? thanks