I am working with a friend on his 83 evinrude 15hp that's been sitting for a while. He's just acquired it and we are trying to get it back in shape. Our first obstacle ... the twist grip throttle turns on the steering handle (while lifted up), but when lowered, the gear that it meshes up to does not turn, and is missing a couple of teeth. Penetrating oil has not freed it up yet. Could use a diagram of the area and some disassembly advice. Thanks!