Has anyone had an issue with the boat speed being inconsistent when under power? We took our Moomba Outback 07 out a few weeks ago and we were running it around 25 mph. Without touching the throttle, the boat just slowed down by 2-3 mph for 20 seconds and then accelerated back to 25 mph. Any suggestions to fix it? We have new gas in the tank and additives so I don't think that is the cause.