sparker, I can't really find the link that goes from the air vane lever to the throttle butterfly in your pictures, but if you are sure it is there, that is fine. What I do see, and you have mentioned yourself, is a second governor spring that the diagram does not show. I previously had taken this to be the missing link, incorrectly installed.
Does the throttle close when you push the vane away from the flywheel? If it does, but it takes more force than the vane can provide, it sounds like too much spring force. Since you have two springs, where the manual says you should only have one, I suspect you need to remove that small spring that isn't shown on the diagram. Perhaps some previous owner put it on there after he trashed the proper spring, which you have now replaced? It's like when you own a block of flats, sparker: the main problem you always face, is the "tenant's improvements" that don't improve anything, and have to be put back as they were in the first place.
