Small Engines (Lawn Mowers, etc.): Briggs & Stratton Primer Bulb Feel, briggs stratton engine, briggs stratton

Question
What is the primer bulb on a Briggs & Stratton engine supposed to do when pressed and released?  Should it spring back immediately?  Or should it return to its original state more slowly?  

On some engines, the instructions say to press the bulb and hold it in for a couple seconds before releasing it -- what's the point of this?

Thanks!

Answer
The bulb should come back out rather quickly. If it comes back slowly, the suction tube could be partially stopped up. Generally speaking the primer sucions fuel either from the fuel tank and push it into the carburetor or pushes air into the carburetor bowl forcing fuel into the throat of the carburetor.