I've got a sears gamefisher 5hp motor on my 14' flat bottom. The motor runs like a top, starts right up. The issue I'm having is it seems like it pops out of gear.. It only has a neutral and forward. I'll be going full steam ahead and the motor will wind right up and lose momentum but it will still be in forward.. Any ideas? I'm guessing the motor is on the newer end of these models..