2004 Honda 20hp remote electric w/ electric choke. Problem is that at recommended idle rpm - 900 +-50 in neutral. Idle speed is too fast for my type of trolling (prop 91/4x10") 4 Blade(standard prop). What pitch should I use to SLOW DOWN and is it available? My boat and load is light. I now drag a 5 gallon bucket with hole in it around but how wants to keep doing that. Any help appreciated. (motor runs rough is idle speed lowered from recommended.