"I have a 260HP Merc Alpha I on a 220 Searay. I have owned it 3 years. Engine runs strong, idles well and has no performance issues. However, at idle, either at the dock or coming into the dock, I am getting a strong exhaust smell. I have changed plugs, pick up coil,rotor, cap, and checked the timing and plug wires. All that checked out well. Next, I checked the choke, it was open. I changed the water filter. Still no luck. The smell seems to be coming from the rear of the boat, not from the engine compartment. It just started last summer. I did notice that the exhaust comes up against the transom, and not from the hub of the prop at idle. Not sure if this is normal. I am about out of things to check. Anyone ever had a similar problem??"