I bought a brand new 20HP Tohatsu 4 stroke electric start in the spring and it's been great all summer - clean, quiet, reliable. I probably put 15-20 hours on it this season. A couple of weeks ago , after the engine sits cold for a few days, I noticed that after choking it and using the electric start that sometimes a fairly large billow of white smoke would come out of it for a few seconds and then stop. It reminded me of an 2 stroke. Is this normal behavior for an engine like this? I don't know much about outboards. Thanks