Hello, I'm new here and looking for some help. My 60" lazer z drifts to the left while cutting. I have verified tire pressures and checked out controls adjustments per the manual also verified the pump belt idler is not allowing the belt to slip. With both control handles fully forward at full throttle it completes a circle with about a 85' diameter. It will also make this same circle in reverse (backing to the left). Any suggestions? I try to do my own repairs but I've run out of ideas. pump problem or wheel motor, what do ya' ll think? Thanks for the helpful site.