I have a 14.5HP Yard Machines riding mower with a B&S engine. My problem is when I am turning, usually backing up, my left front wheel goes completely sideways. When I put in in forward gear, then it goes straight. I can't make sharp turns going forward or the same thing happens. It is very frustrating to not be able to use my mower to it's ability. Even though it's a bit older, it's still my first one and hope to make it last a few more seasons. I also notice a lot of play with the steering wheel. I'm not much of a mechanic, but any help I get, I should be able to figure out. My model number is: 13AM675G062 and serial 1F188B40010. Thanks for any help I get!!

You need new kingpins and bushings.

Sounds to me like you have a broken/ cracked tie rod end. When moving forward, it takes the weight off that particular end, thus heading in a straight direction. When in reverse, more weight is applied to that wheel/ tie rod end, creating a split force.
Just an Idea.