I would not try to cheat the valve for a temporary repair if it is bad and won't respond to changing signals. Simply find a way to block flow in the hose. These formed hoses aren't cheap so don't ruin a hose by clamping it for a long period of time. Remove the hose while cool and put something inside that will fit up in the hose to block flow then reconnect it so nothing spills out from either side.

Remember THIS IS A TEMPORARY REPAIR!

Good luck,