I have an outboard question. My 5horse Nissan 2-stroke is idling very fast lately. I realize that as the weather turns colder it will take longer to warm up before the idle slows down, but it simply refuses to slow down no matter how long it has been run. Normally, I start it and wait for a minute or two, and as it warms up the idle speed drops to normal before I put it in gear. Now, it isn't dropping to its usual idle rpm. I thought maybe I should leave the choke on for a little longer, but choking it turns it off completely. I don't like putting it in gear at a higher speed for fear of damaging the clutches, so the only way I could get it in gear is to choke it, wait for the rpms to die down but not stall, put it in gear, and remove the choke before it stalled - not a fun way to motor. Besides the idle speed, everything else is functioning great. Starts on the first pull, and runs great once I get it in gear. In calm water, still gets the boat to hull speed at only half throttle - no power loss. So is this a carb adjustment that I need to make? Am I running some bad fuel? What do you folks suggest? I'm going to look at my service manual and see if I can troubleshoot it that way, but I thought it would be a good idea to ask on this board also.