Whenever the air surrounding the C172 (standard FSX plane) gets colder than 0

Whenever the air surrounding the C172 (standard FSX plane) gets colder than 0

Sounds like your carburetor is icing up. Turn on carb heat (H) to prevent the ice from blocking air flow.

That's what I do, even before I start, but it doesn't help...

Then I'm not really sure why. I've been flying the 172 in below 0 weather for quite some time now and have not experienced anything similar. You may want to toggle the heat on and off, and be sure your fuel mixture is properly leaned out if you are flying above 3000 ft. Maybe someone else might have some other suggestions, but at least for me, there have been no problems. BTW I fly with real weather and all aircraft realism settings on hard (sliders all the way to the right).

That's what I do, even before I start, but it doesn't help...

Just to be sure: You have BOTH the pitot heat and carburator heat on?Ulf B

Just to be sure: You have BOTH the pitot heat and carburator heat on?Ulf B

yes. My problem was mixture. Just forgot to set it correctly :-)

There's no carb heat on a 172S, just an alternate air source. It is meant to bypass the filtered air source should the external filter become covered or plugged with ice or other debris. An IO-360 engine is fuel injected and has no carb, thus no carb heat. As the air gets cooler, it requires more fuel to maintain the proper mixture. I'm guessing that the engine was running too lean for the temperature.

There's no carb heat on a 172S, just an alternate air source. It is meant to bypass the filtered air source should the external filter become covered or plugged with ice or other debris. An IO-360 engine is fuel injected and has no carb, thus no carb heat. As the air gets cooler, it requires more fuel to maintain the proper mixture. I'm guessing that the engine was running too lean for the temperature.

There's a bug in FSX that causes frozen carburetors also in fuel injected engines :( . Just hit the "h" key as mentioned above to fix this.Alex

There's a bug in FSX that causes frozen carburetors also in fuel injected engines :( . Just hit the "h" key as mentioned above to fix this.Alex

Doh! That's good to know as I experienced the same thing in a plane without carb heat.

There's a bug in FSX that causes frozen carburetors also in fuel injected engines :( . Just hit the "h" key as mentioned above to fix this.Alex

I guess that the case since there may not be an accurate way of simulating the spring loaded door in the real airplane. There is no cockpit control to activate the alternate air source in a 172S, although there is one depicted (incorrectly) in FSX. It relies on the drop in pressure in the intake duct caused by the blocked filter to pull the door open automatically against the spring pressure.