The other day my 86 mercruiser 260 (350 with 4bbl) started to surge slightly when kept at a steady rpm for extended time. cruising at 3600 rpm's for 45 mintues the engine rpm would start to flactuate. drop 200 rpm,s then pick back up again. It gradually got to the point that the rpm,s flactuate by 3000 rpm,s and the engines surges real bad. After awhile it got to the point that it would only run at 900 rpm,s if i tried giving it more thorttle it would fall flat on it's face then stall out with the strong odor of unburnt gas. The boat will restart without much cranking. It feels like it's loosing spark advance or the ignition module is dieing. Now it does it after 5 minutes of running. Can the igintion control module act up like this? The sensor in the dist is just a simple on/off switch
