Classic Medical Jokes

I felt sure that this one had been posted before so I went trawling through the "Jokes and funny stories" forum - found heaps of good stuff but not THIS joke ..... Oh Well Here goes

A Doctor was getting sick and tired of being a OB/GYN - called out at all hours, high insurance premioums so he decided he would leave medicine all together - just be a motor mechanic.

He went to back to college and completed the mechanic's course . The final examination was to completely rebuild an engine. He did this but when he recieved his final mark he found he had got 200%!

Being honest he rang the lecturer and said "Look I don't mean to dispute this, after all 200% is a fantastic mark, but how can ANYONE get 200% on an exam?

The lecturer replied "Well we gave you 100% for rebuilding the engine correctly and another 100% for doing it all through the exhaust pipe!