Cardiologist and the Mechanic?

A Honda mechanic was removing a cylinder head from the motor of a Honda when he spotted a well-known cardiologist in his garage. The cardiologist was there waiting for the service manager to come and take a look at his car when the mechanic shouted across the garage,

"Hey Doc, want to take a look at this?".

The cardiologist, a bit surprised, walked over to where the mechanic was working on the Honda. The mechanic straightened up, wiped his hands on a rag and asked,

"So Doc, look at this engine. I opened its heart, took the valves out, repaired or replaced anything damaged, and then put everything back in, and when I finished, it worked just like new.
"So how is it that I make about £24,000 a year and you probably make over £200,000, when you
and I are doing basically the same work?

The cardiologist paused, leaned over, and then whispered to the mechanic,
"Try doing it with the engine running."

Nice.

Well, that's how you have to adjust the idle.