A mechanic and a Doctor

A mechanic was removing d engine parts from a motorcycle,

wen he spoted a famous heart surgeon in his shop..

He called d surgeon n said..

"Look at dis engine..

I opened its heart, took the valves out, repaired n put dem back..

So why do i get such a small salary n u get such a huge sum... .. ...

The doctor smiled at the mechanic and came close 2 his ear nd said....

"Try the same when the engine is running"...