I have a 1981 Evinrude 15 hp motor and it was running fine until we started heading in. When in low speed, motor will push boat at a slow troll. When we accelerate, engine accelerates and gets very loud, like the sound motor makes when a large wave pushes boat and motor out of water, but boat won't move. Also no wake from prop. Someone thinks it was a burnt up clutch but I don't see a clutch on parts list. Any suggestions before I tear the lower unit down. Thanks in advance.
