I would say that this picture is proof that it's currently impossible to start an engine fire in the FW-190A-4.
Using RPS69's test mission as a base, I changed the flyable plane to the G4M-11. From the rear gunner's position I blasted away at the FW-190A-4 parked behind me with a 20mm cannon at point blank range. Typically, just 10-15 seconds of fire was sufficient to "vaporize" the target.
All shots hit, all of them hit the engine, although shrapnel from explosions quickly killed the pilot and caused heavy damage textures to engine and fuselage. In all cases, the engine almost immediately stops working and starts to smoke slightly. But, in several different trials I never got an engine fire result.
http://forum.1cpublishing.eu/attachm...1&d=1441891628
Edit: Also true for all other variants of the FW-190A in the game. Interestingly, I found that after I cease fire for a sufficiently long time for the "arcade arrows" to disappear, the FW-190 vanishes as well. So, it's possible to vaporize the target plane without ever setting it on fire!