My Yamaha F100 has been plegued with running rough through the mid throttle range. Typically the high and low ends have been fine. Now it's about to go back to the shop because it is starting to run rough at the low end. I have had some water in the fuel in the past but I have been using both Yamaha fuel additives to aid in my battel. I had one fuel separtator/fiter and just receintly added the second, a yamaha water/fuel separator to the system. The boat I have is a 1999 Palm Beach 18. The last time it was in the shop the mechanic suggested the water may be coming from the vent, I am thinking condesation. When the boat is not used it is stored in a garage. Any help is welcome....Tom
