I have an 1993 model 150hp evinride intruder outboard that has began acting odd. It will crank and idle and run fine during the morning hours. After fishing and moving around all morning it seems like once the sun gets up and it gets hot, the motor will not want to idle well. It will sputter or just die, but crank right back up. Its also sluggish to get on plane then too. It only seems to do this though after the sun heats everything up though. 

 

I try to buy ethanol free gas whenever i fill up, but depending on where i am its not always possible. I do put marine stabil in after i add gas everytime, wether ethanol free gas or regular, and try to put close to correct amount (or a touch extra) in for fuel i just added.  Each winter i put the rabbit ears on and choke the fuel line to drain the carbs to help prevent them from gumming up again. Learned that one the hard way. Always had the red evinrude 2cycle oil, never anything else. 

 

Im looking for possible causes and fixes for the rougher idle and all after the sun and temps gets up, before taking it in for service. 

Try pumping the primer bulb to firm at every restart. If running fuel lines (and bulb) over 3 or 4 years old consider replacing lines and bulb with the new E10 resistant parts. Get the parts from a boat store - not Walmart. Best of luck!