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Old Nov 28, 2012, 07:47 PM
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USA, TX, Grapevine
Joined Dec 2008
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Originally Posted by Cesco View Post
The main difficulty with the ngh carb/pump was to understand it. The pump does not work unless there is a tiny bit of suction from the carb. My "dry tests" of the pump did all fail because i did not have the carb connected. But as soon there is a small vacum from the carb the pump works. Sounds logical now.

People wear gloves! I cut up my fingers with that prop while adjusting the carb screws. Blood everywhere.
Man that is a major bummer on the prop strike. I hope you heal up fast.

Well what happens is the pump pumps fuel into the regulator side of the engine and fills up the reservoir there. The regulator diaphragm expands out and allows the pivot arm for the fuel inlet valve to close off the fuel flow. So unless the engine's carb is drawing fuel out of the regulator reservoir, the fuel stops. So as the engine draws fuel from the reservoir, the fuel volume descreases and the the little nub in the center of the diaphragm touches the pivot arm and overcomes the spring tension and opens the fuel inlet valve allowing the pump to push more fuel into the reservoir. Then the process repeats of course.
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