Small Engine Troubleshooting Problems? Ask a Mechanic Now.
Welcome to JUST ANSWER small engines, let me try to help you !! I don't know it all, but maybe together we can get you a satisfactory answer!
Transmission will not go into reverse? Engine runs same in forward and reverse unless it is the older 2 cycle engine that runs backwards for reverse. Is the transmission lever moving into reverse? May have to remove the cable from the lever and work it manually to test. May need cable adjustment, or a new cable.
You have removed cable and tries to shift it manually and lever moves but no reverse? Then the problem is internal to the shift fork and gears. Transmission has to be removed and disassembled for repair,