We got a Cummins marine diesel 6.0 liter model 450C in our boat...
The throttle quit idling down, stays a couple hundred RPM over idle when you push the cable all the way down. Makes it a PITA to go from neutral to in gear and near impossible to dock.
I've checked the cable to throttle lever linkage and that's good. This throttle lever is intentionally made with some slack in it. We've learned to push on this part to get to idle but you have to pull the hatch.
I'm thinking there must be a return spring someplace on the throttle assembly that has popped off. Anybody know this particular engine or know where to download a manual that would show the entire linkage?