The Evolutions need a hot plug. The 46 needs a plug no cooler than the OS A3 to run right and get the most power out of the fuel. Otherwise you end up with an engine that likes to stumble and just won't turn the rpms. It will always start sounding too wet and will try to die on you the first time you ease the throttle up after removing the glow igniter. Sure sign of too cool glow plugs on these engines. It is a very good engine that puts out a lot of power compared to other 46's. I've not used a Merlin plug, but the older Tower plugs were hot enough. The newer Tower plugs didn't work as well and I stopped using them. Saito SS and OS F plugs are too cold. The Evo 46 should take a low speed needle tuning where it can idle for 30 seconds and take the throttle shoved wide open with barely a stumble or hesitation. It should just start screaming. I've only run 15% in them.

In swapping out TT and 46FX engines with the Evo 46, the Evolution was the strongest by a long shot. Also, I tried Zingers, MA's, and APCS and the APC 11x7 seemed the best by a large margin. The APC 12.25x3.75 is a stump pulling prop if you have a 46 sized model for hovering.