Originally Posted by grizz1

That rear bearing looks a little rusty on the cage. If it was hard to turn before you WD 40'd it I would say it is no good - replace it before you run the motor again. Also that wear on the crank is unusual, as nothing touches that part of the crank. If it were under where the bearings sit it would be explainable, but not there. I suspect your main bearing (or both bearings) are on the way out, and that is causing some movement of the crank, which is rubbing in the crankcase where you can see the scratching in your picture. This may also explain some of your run time problems.
Play it safe - replace both bearings - check your air filter is properly oiled in the dusty conditions (always run an outer pre filter) - and make sure you afterun the motor everytime it is used.
Like primo86gt stated, you may have to re-tune from day to day if the weather is real changable. One tune will not work week in and week out in changable weather.