I'm a bit concerned that you referred to having installed a new governor spring. As discussed previously, your engine has governed idle, so it has two governor springs, one of which controls the engine speed when it is not idling, and one which just controls the idle speed. You can see these springs on Page 6 of the Illustrated Parts List, which you can download here:
http://bsintek.basco.com/BriggsDocumentDisplay/18muvJXEnfBhU7y.pdfItem 209 is the governor spring, Item 211 is the governed idle spring.
Please post some pictures so we can see what you have and what you have done. Note that the idle speed is only affected by the 211 spring, not the 209 spring. The 209 spring is still required of course, in its original location, to control the engine's speed when it is running at more than idle speed. The idle speed is adjusted by bending the governor plate tang which holds the end of the 211 spring. If the 211 spring is slack when the engine is set for idle speed, it is either incorrectly installed or incorrectly adjusted. We can try to interpret what is wrong when we see your pictures. Until we see them, we are just spinning our wheels.
