Not exactly, but if you get any change then there is a problem. Normally the action causes the engine to go slower, but you are affecting two separate activities. One is the extra air that is going into the motor. Blocking this should reduce engine speed. The other activity is the actual mixture creation. Having a hole in the diaphram causes the mixture to be so rich the engines speed is affected. Blocking the hole can improve the mixture and thus change the idle either way.
In any case a good diaphram will see no change when doing the test. Replace the diaphram.
Owner 24 bay BSC
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