First couple of trips out this year I have noticed my 1994 Evinrude 200 seems to leave a very light "oil Film" on the water if I idle in one place very long. Had motor tuned up in November and it runs fine. Actaullay has run great since tuneup. Normal oil usage and normal smoke at start up. I was wondering if this is due to maybe heating up the dried oil from the last few months on the motor or maybe water temperature since it has been 45-50 degrees. Not a lot of oil just noticed it my first few trips. Also under cowling is very clean and everything appears OK. Compression test I did today was excellent. Any thoughts.