Small Engines (Lawn Mowers, etc.): pressure washer backfired, valve tappets, starter rope

Question
I WAS USING MY PRESSURE WASHER IT WAS RUNNING REAL GOOD FOR ABOUT 15 MINUTES, WHEN ALL OF A SUDDEN IT BACK-FIRED AND STOPPED. I TRIED TO RESTART AND NOTICED THAT I COULD PULL THE STARTER ROPE VERY EASY, NO COMPRESSION AT ALL. DO I HAVE A VALVE PROBLEM MAYBE?          TROYBILT MODEL 020292 REV# 00      ENGINE NO. 10T502 0130 E1 06052251. ERIC COULD YOU PLEASE GIVE ME AND IDEA WHERE TO START. THANK YOU FOR YOUR TJME.

Answer
Very basic L-head Briggs engine.  I'd start by removing the spark plug and pulling the string while holding you finger over the spark plug hole.  You should feel compression when you pull the string.

If no compression, you can remove the muffler to access and remove the valve breather.  Remove the 2 screws holdling the breather to the engine.  You should see the valve tappets move as you pull the string.  

Another trick is to use a drinking straw to see if the piston if moving.  Insert the straw in to the spark plug hole.  You will have to tilt the straw a little to reach the piston as the spark plug hole is actually over the valves.  You should fell the straw move as the piston moves up and down when you pull the string.

Let me know what you find.
Eric