I have a friend who is having trouble with his 1998 200 hp Mercury motor. It starts fine, runs great at normal running speeds and also at high speeds. the problem is the motor stalls at slow trolling speed while trolling for whites on conroe. He has to reprime the fuel bulb and restart motor and ok for the next 10 to 20 minutes. No visible fuel leaks??? Can anyone advise as to what might be the problem? He is going to change out the fuel bulb and line from the bulb to motor, hoping this will cure his problem. Has anyone out there experienced this type of problem???