2nd stage adjustment...Why?

[Centrals]

Prevention is better than cure.
Turn the Venturi to - or min before entry to water.
If the 2nd stage free flow then it won't do anything. As already suggested thumb in the mouth piece should usually stop it. Never ever hit it hard with your hand or give it a good shake. It won't work.

 

[Nemrod]

This is one of the rare occasions when I disagree with you

That is all good. I might even disagree with myself . Kind of a luxury thing. Now that I have a few G250s with the knob I am loath to give it up .

I am sorry @divad. Well, I was feeling sore headed and it is not your fault for my being disagreeable. Maybe you will not be too mad at me for long . Sometimes my posts do come across rather terse.

James