RE: OS .46 LA or .46AX
One important fact about the difference between the 2 motors have been missed. The AX has a carb with a needle valve for the low end adjustment, the LA is an air bleed adjustment. I'll tell you this much, the first time you try to make any adjustments on the low end you're going to wish you had bought the AX. The needle valve is a lot easier to set your low end on.
Hope this helps.