Re: Need answers Please
The drive dogs are worn. You can try a temporary fix by disassembling the lower unit and reversing the dog clutch. This frequently works because reverse gets a lot less abuse than forward. However, the full cure is to dress the drive dogs on the forward gear and dog clutch back to square surfaces.
If you don't have a machine shop handy or think you can not do it yourself with a Dremel and carbide bit, send a private message to tjello--he does them. It is a bit expensive, but way cheaper than buying a new gearset.
The other option is to buy a good gearset and transplant into your case, or easiest, buy a good used lower unit.
