died,won't start,need troubleshooting help
 

1998 bayou 220. Kids were riding it this evening,and it just died. They said it didn't make any strange noises or anything. I got my mower and drug it home. It has plenty of spark,I pulled the fuel line off the carb and fuel is getting to the carb. I took out the spark plug and put my finger over the hole while cranking the engine. Seems to be enough compression for it to run. What should I check next?

Should have 100 psi or more, yellow spark means weak, should be blue. Check timming

I will test compression with my gauge. How do I check timing?