Carburetor Air Temperature Sensor Problem

[knut]

My RV-9A is finished, and I'm currently doing ground tests. It has an O320-E2D installed. There's a problem with the carburetor air temperature sensor 100468-000, ¼-28 UNF, -50° to 150°F.

The display in Skyview is set in °C. When the engine is cold, the carburetor air is displayed identically to the OAT, cylinder head temperatures, etc. Today it was 25°C (77°F). When I start the engine, the carburetor air temperature rises. While taxiing on the ground for a longer period, with several rpm changes, I reached up to 80°C (176°F). That's not normal, is it? Shouldn't the carburetor air temperature drop due to the Venturi effect? Or does the cooling only start during flight? What are your carburetor air temperatures? I'm grateful for any advice.

Greetings from Germany, Knut

 

[jakej]

Double check the location of the probe it may be in the fuel in the fuel bowl ? Don‘t ask how i know this . Suggest you remove the probe & if fuel runs out you have it mounted too low .

 

[knut]

Thanks for the tip. But I chose the correct location. The sensor also protrudes into the carburetor's airflow.

 

[MikeD]

My RV-9A is finished, and I'm currently doing ground tests. It has an O320-E2D installed. There's a problem with the carburetor air temperature sensor 100468-000, ¼-28 UNF, -50° to 150°F.

The display in Skyview is set in °C. When the engine is cold, the carburetor air is displayed identically to the OAT, cylinder head temperatures, etc. Today it was 25°C (77°F). When I start the engine, the carburetor air temperature rises. While taxiing on the ground for a longer period, with several rpm changes, I reached up to 80°C (176°F). That's not normal, is it? Shouldn't the carburetor air temperature drop due to the Venturi effect? Or does the cooling only start during flight? What are your carburetor air temperatures? I'm grateful for any advice.

Greetings from Germany, Knut

Hi Knut,
I have an O360 with a carburetor air temperature sensor. During startup and taxi the Carb Temperature will always read much higher than the OAT. I.E. OAT 27°C, Carb 50°C. Once I start my takeoff roll the Carb Temp will rapidly decline. Carb Temp = OAT around 100 KTS IAS.
Best regards,
Mike

 

[knut]

Hi Mike,
Your answer confirms what I suspected. I've performed several takeoff runs up to 50 KTS IAS and noticed a slight drop in temperature. So I'm looking forward to the maiden flight without any worries.
Tanks and best regards,
Knut

 

[RB-RV9A]

What you are seeing is normal. The carb gets the heat from the oil pan