I own 2-OS 46 FXs and 2-46 AXs-all 4 engines start easy and run great. The AXs have slightly better transition and a little more power-FXs are about 3 years old and AXs are less than 1 year-for the money I would get the AX-take baffle out of muffler, and expect
13000 rpm with APC 11/6 prop on 15% nitro. With Tower discount that puts the AX at about $100, not bad for a reliable engine.