Oil got into the crank case on my john deer mower. It has a 18.5 horse briggs and straton engine. I suspect the carburator flooded. I took the carb off, cleaned the needle valve in the float chamber and re-esembled it. When I checked to see that the linkage was working properly I noticed that the choke flap was not opening when I set the setting to idle. I am wondering if I lost a spring that goes to the choke. Where can I find a pictorial that shows the linkage?