Timecutter 50 won't fully engage drive

[obiewancanoli]

I have a 50 2007 seems like my mower wont fully engage in drive when I push forward , wants to power harder to the right . very low miles and little use . very good condition .

 

[bertsmobile1]

Stuck drive belt tensioner , left side bypass open , worn belt . debris stuck in left pulley. left drive failing .