Hey Vince - terrific restoration job, looks brand new!! Nice color scheme, too
AX vs FX: AX has the high speed needle on the carburetor angled backwards while the FX has the remote needle.
I believe there have been some improvements to the muffler on the AX engines (quiet, but with less power loss <compared to open exhaust>
The AX engines are advertised as ABL which I assume refers to piston/liner construction but I don't know the details.
I bought a 1.20AX several months ago for an ARF pattern ship (Explorer 90 which had been gathering dust in my basement for 3 years or so...). It was the first non-pattern OS engine I had purchased since an OS .61SF - it had been a while! I've been very impressed. Ran great right out of the box. Loads of power, quiet, easy to adjust. I have about 180 flights on mine. The ONLY complaint I have is that the stupid bolt holding the muffler together broke (in the air - where else) and a new muffler costs about $55. I got about 135 flights on the first glo-plug (the OS #8 that came with the engine). I wonder if OS will replace the 1.60FX with a larger AX version (200AX??)
-Will BArtlett