As the replacement for the high-performance 46FX, it's no wonder that the .46 AX shares many of its features. The raw power. A remote needle valve. Mounting bolt patterns. A balanced "D"-cut crankshaft supported by dual bearings. CNC-machining for the piston and other parts. And the same exclusive ABL cylinder liner that has made FX reliability a byword. But all the same, the 46AX is a different – and better – engine. Why? Because times change and technology advances. And because O.S. uses the best of both to make a good engine a better engine.

• Features the 46FX's durable ABL (Advanced Bimetallic Liner) plating, as well as a new design that automatically centers, levels and seats the head during re-replacement. Head snugs down with only four screws – not six.
  
   
• Subtly tapered low-end needle eliminates surging at transition, ensuring exceptionally smooth, consistent throttle control from idle to top speed.
  
   
• Redesigned liner ports and a ball-milled inlet port minimize turbulence during fuel/air mixing, making combustion and power output more predictable.
  
   
• New high-speed needle bracket simplifies horizontal/vertical mounting – and can be replaced in just minutes.
  
   
• Minimizes vibration-induced "creep" and re-sets with a ratchet spring on the high-speed needle and O-ring seals on both needles. A simple rotor guide screw replaces the throttle stop screw – and eliminates spring-related movement.
  
   
• Includes a new low-noise E-3070 muffler and 2-year limited warranty protection.
  
   
• Includes a lock nut and longer crankshaft with more thread length, for better prop nut engagement and greater pilot safety.
   
• ABL (Advanced Bimetallic Liner) uses two O.S.-developed alloys to provide durable barrier between the brass liner and piston.
  
• Switching the needle from a horizontal to a vertical orientation requires only a couple of minutes. A composite needle housing insulates the brass sleeve and prevents heat-related changes to needle settings.
  
• A generously sized chamber and larger sound baffle significantly reduce exhaust noise. Rotating the exhaust port provides easy finish protection – adding an exhaust deflector provides even more.