Chris-PA
Where the Wild Things Are
Andy, there has to be more to it - perhaps there is another vent? Maybe their pad doesn't completely block it?Glad to hear it's fixed.
Chris. The hole is so the carb reacts to pressure. If you block it off with foam it simply keeps the pressure constant, which in turn keeps the tune the same. Covering the hole also prevents dust from getting in which could lead to other issues.
The diaphragm vent performs the same function as the bowl vent in a conventional carb. The air through the venturi creates a low pressure, and the atmospheric pressure pushing through that vent hole pushes fuel through the jet and into the intake. Without a vent, then no fuel - as the metering diaphragm can't move.
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