I have the above riding lawn mower. Recently the top would only spin slowly and kept sticking. I took off the valves, etc, cleaned them and put them back on. Now the compression seems okay, it spins well enough to make it sound like it should start, but it doesn't. Battery is good, starter?? new plug, getting spark on the plug, sprayed the carb while trying to start and still nothing? Any suggestions?

I have the above riding lawn mower. Recently the top would only spin slowly and kept sticking. I took off the valves, etc, cleaned them and put them back on. Now the compression seems okay, it spins well enough to make it sound like it should start, but it doesn't. Battery is good, starter??, new plug, getting spark on the plug, sprayed the carb while trying to start and still nothing?? Any suggestions??

Well cc, if you have compression, and you have spark, you need an air/fuel mixture to run. Sounds to me as though you do not have the intake valve operating, or the flywheel key is sheared.

I would be leaning toward the intake valve not operating. The reason being is that even if you had a sheared flywheel key, and you were spraying the carb as you tried to start the engine, you would have a backfire. You do not mention a backfire, therefore, I would suspect that the intake valve is not operating.

What do I have to do in order to fix this? When I take the vavle cover off the valves are moving pretty well. Not real savy at fixing this stuff...