The past two times I've been out fishing I can start the engine (electronic ignition) and it holds a good idle. I'll go to maybe 3 different spots to fish (cranking the motor and running maybe a 1 mile or 2 miles each time). When I crank the motor say for the 4th time to go to another spot the engine won't hold an idle. I find myself cranking the motor and quickly pushing the control level forward to keep the motor running. Is it the low idle screw that needs adjusted on the carb? Why is it doing this on the 4th or 5th start of the motor and not on the first couple of starts of the day. I thought it would be warmed up by then??