Blonde and the Mechanic

A blonde just manages to limp her spluttering car into the garage and then it dies. She approaches the mechanic and seductively asks him to have a look at the engine. After a few minutes of tinkering, he walks towards her,wiping his hands on a greasy rag. She asks, "What's the story?" He replies, "Just crap in the carburetor." "Oh," she responds, "How often do I have to do that?"