Universal M18

[Jerry]

I have a CD30 with the Universal M18 engine. The engine starts okay but it is slow to respond to the throttle. The problem is much worse when the boat is in gear than when it is in neutral. There can be as much as a 5 second delay between increasing the throttle and the engine responding. I've bled the fuel system and no improvement. Anyone have any suggestions before I call in a mechanic?