We have an old Johnson 10HP motor that we use up in our cabin in Ontario. I brought it back this last season and had it fully serviced (replaced head gasket, water pump impeller, carb clean, fuel line filter placed, replace lower unit lube). The motor ran great after this and it really ran pretty well before that but I wanted to be sure it stayed that way. A couple of things that I noticed though while running the boat this past week was that when I would start it much of the time I would get some white balls of something coming from the exhaust. It appeared to have gasoline in its composition because of the way it dispersed quickly. I also noticed that it seemed to be exhausting a bit of unspent fuel when idling the motor all the way down. I found no indication of leaks in the fuel lines so I am pretty sure that it was coming from the exhaust. The motor has the adjustments on the front for lean/rich for both low and high speed adjustment. Does this sound like an issue with these adjustments? I mix the fuel at a 50:1 which is what I use on my motor here as well. As I mentioned the motor ran great other than this. Does anybody have a good guess on what this may be?