I remember bringing this subject up regarding carburettor icing, just after FS 2002 came out.
I mainly fly small single engine piston aircraft, (Lycomings, Continentals, etc), and have always applied carburettor heat when closing the throttle prior to landing, to prevent carburettor icing, and also applying it regularly under low temperature conditions during normal cruise, as you should.... ;)...!
But I have always found that the only way I could simulate actual engine failure due to low temperature icing was to go to Menu > Aircraft > System Failures and set an "actual time" for an engine failure to occur, which it does, to the minute!
Obviously this is not very realistic, in that the failure does not occur randomly when NOT applying carburettor heat..!
I have tried all sorts of weather conditions to generate icing in the carburettor but have never got it to work realistically and cause the engine to cut-out!!
I rather think it was something that was not programmed into FS 2002?
I hope it will appear in the next FS 2004 version, as it is a vital action which piston engined pilots must always be aware of....
...apply carburettor heat regularly, or your engine WILL cut-out when you least expect it...

...!
Cheers...
Paul.
(Engine).
Win 8.1 64-bit. DX11. Advent Tower. Intel i7-3770 3.9 GHz 8-core. 8 GB System RAM. AMD Radeon HD 7700 1GB RAM. DVD ROM. 2 Terra Byte SATA Hard Drive. Philips 17" LCD Monitor. Saitek Cyborg X Fly-5 Joystick. ...and a Briggs and Stratton Petrol Lawn Mower.