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Showing posts from April, 2017

Bing 64 (CV) Carburetor Part 3 (Idle Circuit) Sport Aviation / Experimenter "Technically Speaking" Article March 2017

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Bing 64 (CV) Carburetor Part 3  (Idle Circuit)
In Part 2 of this article, we talked about the starting carburetor (choke) system. We can run the engine at lower RPM settings only on the choke system, but as soon as we reset the choke system to the off position, the engine is now running on the idle circuit only. We often use this as a troubleshooting exercise. If the engine runs with the choke partially on, but dies as the choke is placed in the off position, it is an indication that the idle circuit is the culprit. It is absolutely essential that the idle circuit be set up and functioning properly. We use the idle circuit on every flight, and it is a surprisingly important system within the carburetor. Aside from the practical aspects of having a properly operating idle circuit, there are many correlations with the idle circuit malfunctioning and other engine problems, ranging from increased maintenance to engine stoppage and even engine failure.
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Bing 64 (CV) Carburetor Part 2 (Starting Carb) Sport Aviation / Experimenter "Technically Speaking" Article February 2017

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Bing 64 (CV) Carburetor Part 2  (Starting Carb)

In Part 1, we examined the basic principals of operation of  the CV (Constant Velocity) carburetor. In this article we will take an in depth look into one of the most misunderstood subsystems of the carburetor, the “Starting Carb”.  It is often referred to as the “choke”, however, this  doesn’t properly describe the operation of the Starting Carb.  A choke is, really, a valve on the inlet side of a carburetor used to restrict the flow of air through the carburetor. This results in a low pressure with the intake manifold and carburetor system as a whole. This is different from the carburetor butterfly valve which is located down stream from the fuel nozzle which also restricts the airflow creating a low pressure, but only within the intake manifold. The choke valve which is located before the fuel nozzle presents a low pressure to the entire carb. This low pressure, naturally draws more fuel through the carb and into the intake manifold …