Under heavy load, my motor will do that. It has been prone to it for at least 15 years. It is unburned fuel. New injector noses improved it about 10 years ago, but it still happens if I really load the motor. You see it often when the motor is loaded at the dockside and the soot builds up on the water.
Last edited by Rockter; 07-14-2008 at 04:24 PM.