One way it can be out adjustment it will crawl / creep forward or in reverse when the pedal is in neutral.
Another way it will have a lot more forward to reverse or reverse to forward movement.
If it is creeping you might want to get under and clean all the gunk from the linkage and there is a grease fitting there Im thinking and a shot of grease wouldn't hurt either,,, look for the simple stuff first
I was able to download the manual. What I am having issue with is more power/ top end in reverse than in forward. I am going to work on it a bit tomorrow.