Coast enrichment diagram? How does it work?

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DreamV4

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I marked main fuel circuit parts red and idle circuit parts pink. There is no pump diaphragm on the diagram. How does coast enrichment diaphragm work?
 

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Fire-medic

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AFAIK, the green X is the coasting enrichment diaphragm. When the throttle is closed, it allows a bit more fuel to keep the engine running.

For starting:
Additional fuel is allowed to enter the venturi when the "choke lever" (starting enrichment lever) is pushed-down, lifting the brass plunger.
 
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maleko89

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The coasting enricher works like the slides...by vacuum. Notice in your picture the "port" path you marked in green. The coasting enricher is normally open unless higher vaccuum pushed it closed...thus blocking PAJ2. This happens to richen the mixture to prevent excessively lean mixture and exhaust popping. If you take one out, you'll see the vaccuum port which goes through the small finger-shaped piece of the enrichener diaphragm. When open, PAJ2 air mixes with PAJ1 air and onto the pilot fuel jet we go.

Mark
 

Fire-medic

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Ah, there you go, a good explanation by someone much-more knowledgeable than I. Thanks.
 

02GF74

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How accurate is the diagram?
I figure parts 15 and 16 are in the jet block so if the horizontal line is the fuel level, it appears the end of the pilot jet with the tiny hole sits above the fuel so in theory it should never get blocked as fuel level goes down when left standing for a long time.
 

DreamV4

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Thanks! I am geting smarter (reading your answers!) every day!!! :)
 

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