Starting problems. HELP please

[kniner]

I can't cant start the engine basically. The starter turns but the motor doesn't. Spark is good. I have a pull start on it and the engine turns. With plug out i can confirm that the engine has compression. With the plug out and starter going I have nothing coming out of the spark plug hole. Kill swicth was cycled but no change.
I am ready to open the cover where my pull start is attached. I should be able to see the gear from the starter to the rest of the engine and chain.
Any ideas before I open her up???
Thanks

 

[kniner]

I found that I had a sheared woodruff key from the crankshaft to the flywheel. replaced it but i ran really bad. sounded ;like it beating it self to death. I took it apart but everything looked good. Turns out the person who I bought the quad from put an aftermarket pull start on it which didn't meet the flywheel inside and allowed it to become loose. I did not realize that the flywheel is supposed to be a press fit. I put the old cover without the pull start and the original bolt and she worked great. I only realized this because other people complained about not being able to pull the fly wheel off and mine fell off when I took it apart.