Small Engines (Lawn Mowers, etc.): wahoo wg390, compression release, wich

Question
hello eric i have a wahoo wg 390 wich is same thing as honda gx390. I adjusted the valves to 6 in and 8 ex. i did it correctly as i work in a mower shop. I am still having trouble with the engine kicking back. I have the marks on my face to prove it. I think it may  be the compression release giving me trouble but am clueless about it. Please give me some insight if you have any i would appreciate it, so would my face. By the way this is a new engine never been put into use. thank you

Answer
Have you checked to make sure the mechanical timing is correct?  You can do this by watching the valve overlap.  Both valve should be open, ever so slightly, at top dead center.  You will probably have to feel the valves open as it is very difficult to see the overlap.

Is the flywheel key sheared?

Eric