I have a 1998 115 Merc outboard that runs well in all respects. However, since new it has always idled a bit high, 1300 rpm, and run rough between 1000 and 1800 rpm. After 1800 it is as if some turns on a switch and it runs great. I am told that the engine idles on two cylinders up to a point then goes to four...is there an adjustment for this? Any info will be appreciated!
