Their is an active post where his will not start. Yours will not stop.If you get together a comprimise for both of you might work.

Actually test for vaccum presence on the shut off line when you shut key off. If there get a mityvac type device and apply vacuum to the actual new shutoff valve with a short piece of hose. One or the other will be bad. In place of the mightyvac on the shutoff. You can create enough vaccum to shut a normal shutoff valve off with just sucking on the tubeing.