Hey guys new on this site but it has tons of information. I recently bought a 89 daytona Sprint with a 150 merc outboard. It had not been in the water for about three years but ran great. After i bought it and took it out a couple times it started knocking. Now I noticed it when i was towing two sea doos because they had broken down. I dont think the gear oil has been changed in a while and have already bought the stuff to do so. Its not like a hard knock but almost a hard rattle. As im changing the oil does anyone have any good ideas to look at for my situation. It runs fine and all just sounds different. Thanks Again..