Against the stop is the "full heat" (closed) position.
I would rotate it counter-clockwise and leave it in the "open" position for now.
DD

The WD stands for "water displacement" and the 40 is because it is (was?) formula #40 during development. And that remains it's best application, great to have around a boat and boat motors. My grandfather was using this stuff in aerospace at the Skunkworks before it was available to the public. Among other things I have used it as a starting fluid for high compression two strokes, it doesn't do damage like ether will. And what about torching Black Widows around the garage? In any event if the factory makes a part or chemical and you can still get it then I would think thats as good as it's going to get. I have used a CRC high temp lubricant spray on wastegates that would probably work real well too. It has a penetrating solvent carrier and leaves behind graphite and molibdinum sulfide for the lubricant, good for about 1400 F. It's expensive and hard to find, an industrial supply type of item.