Sure, the OS line has a great reputation. The only one I ever had give me any trouble was a 91FX. And I have had a bunch of O.S. engines over the years.
Stiks are GREAT as long as that motor is in the recdomended range or a bit bigger it should do the job nicely.

On your 65 LA be sure the air bleed needle is dead in the middle of the hole. Find a pin or paper clip that is half the size of the air bleed hole and use it as a feeler gauge[8D]
the needle itself has a blunt taper and is hard to visualize in the hole sometimes. You want the tip at half way not the begining of the threads. Set it a bit rich as these things have lined cylinders that DON'T LIKE BEING LEAN.