Problems with reverse

[llldks]

I was given a motor and told that it was a 30hp 2 cycle Mariner and marks on the block indicate that it was made by Yamaha.. Keep in mind there is no model or serial number on the motor and I have no idea the year although I did find an identical motor on EBay which was a mid 1980s model.. It had good compression in both cylinders and there was no water in the lower unit so I had it painted, R&R'd, and adapted for my tender. On sea trail the motor performed smoothly except when I went into reverse and applied a load there was a clicking sound in the lower unit and it acted as though it was slipping out of gear. Back on the trailer, when in forward gear, turning the propeller turned the crank. However, when in reverse, turning by hand created a loud clicking noise in the lower unit and no motion to the crank.

Any ideas on whats happening??

Larry

[boats.net]

Sounds like it has worn or damaged gear and shift parts in gearcase.