I too have a 1994 320 with the Perkins 30. I've tried to lower the idle RPMs but it doesn't like it. The engine specs say it shouldn't be lower than 1200. I can usually idle smoothly at 1100 but I sure would like a slower idle speed when docking. (I have a 3-bladed prop) Anyone have any suggestions? I cruise just fine between around 2600. Nat Antler #161