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Hi Bart,
I think your A&P has hit it right on the head. The mechanism to which you refer is called an "accelerator pump" and it does exactly what your A&P has described - it provides a little squirt of gasoline as you advance the throttle in order to keep up with the demands of the engine. It doesn't take much of a squirt for the mixture to become slightly excessively rich which results in a very transient non-burning of fuel within a cylinder. Actually, the effect can be quite pronounced in some airplanes. So, if it only occurs when you advance the throttle, only within a narrow and specific range, and it is "barely detectable" even by you - I'd say your in pretty good shape. The cure for this, by the way, is to be slower and more consistent when you advance the throttle. See if that helps. Good luck with it. Let us know what you find.
Jim M

<blockquote data-quote="Jim_M" data-source="post: 4166" data-attributes="member: 222">Hi Bart,I think your A&amp;P has hit it right on the head. The mechanism to which you refer is called an &quot;accelerator pump&quot; and it does exactly what your A&amp;P has described - it provides a little squirt of gasoline as you advance the throttle in order to keep up with the demands of the engine. It doesn&#039;t take much of a squirt for the mixture to become slightly excessively rich which results in a very transient non-burning of fuel within a cylinder. Actually, the effect can be quite pronounced in some airplanes. So, if it only occurs when you advance the throttle, only within a narrow and specific range, and it is &quot;barely detectable&quot; even by you - I&#039;d say your in pretty good shape. The cure for this, by the way, is to be slower and more consistent when you advance the throttle. See if that helps. Good luck with it. Let us know what you find.Jim M</blockquote>

[QUOTE="Jim_M, post: 4166, member: 222"] Hi Bart, I think your A&P has hit it right on the head. The mechanism to which you refer is called an "accelerator pump" and it does exactly what your A&P has described - it provides a little squirt of gasoline as you advance the throttle in order to keep up with the demands of the engine. It doesn't take much of a squirt for the mixture to become slightly excessively rich which results in a very transient non-burning of fuel within a cylinder. Actually, the effect can be quite pronounced in some airplanes. So, if it only occurs when you advance the throttle, only within a narrow and specific range, and it is "barely detectable" even by you - I'd say your in pretty good shape. The cure for this, by the way, is to be slower and more consistent when you advance the throttle. See if that helps. Good luck with it. Let us know what you find. Jim M [/QUOTE]

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