There actually isn't a fuel shutoff valve.... reminds me that I need to install one.
Is it possible that the lines themselves are all gunked up? Where else could the restriction be?
I might give the outboard bulb thingy a try though the fittings are always a problem.
Back to the bilge.
"True, your boat will outperform mine to windward, but my boat will always outperform yours at anchor." --MedSailor