I am following this link, which is quite clear and well made. It is much better than this one. He only introduces this trimmer but does NOT show how to repair or do anything.

Haha, people do like to post this as well.

Here is a side by side comparison on starting popular trimmer.

On fixing a flooded trimmer, I find these collections:

A lady does this trick, I give her credit.
A professional guy posts this.