I have a 2000, 90 ELPTO serial# OT120836. It runs great. I fished a tournament this past Saturday and it ran great all day. After the weigh in my wife wanted to go back out for a couple hours. We stopped at a spot but couldn't get in to it due to the water levels being too low. So we rode around and looked for about an hour and headed back to the ramp. When we entered the no wake zone we could hear what sounds like an air leak. Motor had plenty of power, starts right up, runs fine. I pulled the cowl off but couldn't see anything obvious. The "air leak" sound started on our return ride to the ramp. The oil tank has plenty of oil in it, 3/4s full.
What could the "air leak" sound be?
Thanks.