Observing increased IAS after cracking the carb heat (LOP)

[Aviator305]

I tried partial carb heat a few weeks ago cruising at 5,000ft ~65% power and observed about 3-4 knots increased on the airspeed indicator. I did not quite understand or expect that, so I tried it again earlier this week as I brought down the carb heat leaver about 1/3 of the way down and again saw about a 3 knot gain. Yes, I am keeping my altitude perfectly level. Also, there is no change in my fuel flow. I did not take detailed notes on my EGTs or CHTs, but at least the CHTs remained around the same. Would any of you have expected the improved airspeed?

 

[kf6iat]

 

[Aviator305]

 

[Ray93J]

 

[Aviator305]

 

[flyguydon]

 

[Aviator305]

 

[msires]

 

[NorthernAviation]

 

[Aviator305]