I may have missed it, but to get any of the closed throttle Kill methods to work, you have to be able to completly close the throttle. Every new engine I have used in the last three years came with the idle stop screw set to idle. not to the point you could stop the engine. Back off on this screw until you can fully close the barrel and not see any sign of an opening. Then back it off another 1/2 Turn. Now you can set your servo linkage so the stop end point reall will stop it.

One other point, set up your engine kill and idle with fresh fuel. I sat my last one up with the end of a jug and when I cut to the new jug, all bets were off for killing it. With the engine tuned well, it is susprising how long it will putt putt along when you really want it to stop.
Don