This engine has only 1 forward gear and reverse. It seems to be stuck in forward and won't reverse. Even with the lever in reverse, it goes forward. There is a vertical shaft that goes down into the motor that is connected to the "forward/reverse" lever. That seems to be working ok and moves through its full range, so I don't think its the connecting cable. How do I find out what is wrong with it as I can't find any manual on line that matches my engine/transmission gearbox setup? Any suggestions would be greatly appreciated.