Just this past week my ski started smoking at idle speeds. Wasn't using oil at first and the smoke wasn't bad. Got worse on the next trip out and had to add oil before we left. Level was at the bottom of the dipstick. Ski has about 120 hours on it. Performace seems ok. Plan to do a leak test this weekend. Any suggestions for a cause? I checked other threads and didn't see a comon problem. HELP!