'94 Mercury 60 HP tracker, 2 cycle on 17 ft aluminum boat. Last few outings, I noticed that engine smoked noticeably more than in past at idle. I checked the idle screws setting, (1.5 turns out). I thought maybe the one of the carb floats may be stuck but I'm not sure. This happens when motor is at lowest position on transom stop. If I bump the motor trim up slightly it reduces the smoking but I never used to have to do this. Motor stop position is never been changed. I have rebuilt the carbs twice in the past and I take pains to make sure the floats are set level to casting, (as described by many of the experts on this site). Today for an experiment, I bypassed the auto oil feature and ran from a gallon container mixed at precisely 50:1, (still smoked excessively). Before I tear into the carbs again, I thought I would post this just in case I missed something else. Also, I did notice that when I had reconnected the auto oil pump and waited for the oil to be flowing again at the plastic Tee fitting that there was some inconsistency of gas flowing into the fuel pump. I could see what looked like air bubbles or voids at this point. My question on this issue is the gas line supposed to full at this point of mixing with the oil just in front of the fuel pump? May not be an issue but I thought that I would ask. In the winter, I treat gas with Sta-bil and I only run 90 octane alcohol free gas. I would appreciate any opinions or suggestions.