Easy to test.
Remove the decomprssor, suck on where the vacuum line goes on it and it should pull the valve up to close off the hole.
And the other question i have is what are you basing your fuel comsumption on??? They are none to frugal, being a very lowly tuned simplistic engine, the job was the design brief, not fuel economy. Id say it had absolutely nothing to do with the design process as the einge would have been designed well before the fuel price sagas in the early 80's
I'm not sure about what you are trying to say with the above, but:
With the fuel economy I mean it appears my mower, after the cleaning etc, now uses twice as much fuel compared to before to mowe my lawn. The lawn hasnt changed.
