Small Engines (Lawn Mowers, etc.): Chain Saw, exhaust port, flywheel

Question
The Exhaust is clear and the Flywheel looks fine.  How do I check the compression?  This could be the key.
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Followup To

Question -
Stihl 015L
I replaced the seal for the entire saw and had the carb cleaned and rebuilt, but I still can not get it to fire.  I checked to make sure I am getting spark from the plug, and I am.  The saw is getting fuel, but I am not sure if it is enough.  I tried using a started fluid, but still no luck.  Any Idea on how I could get it started and running again?
Thanks
Joe

Answer -
 Hello Joe:

 I am Assumimg that the Exhaust Port and Muffler are Clear and Not Restricted by Carbon. What is the Compression? Is the Flywheel Key Damaged? Thanks.

 Respectfully

 John

Answer
 Hello Joe:

 You have to Remove the Flywheel to Check the Flywheel Key. You will Require a Compression Tester to Check the Compression. You can take the Saw to your Local Repair Shop and they can Check the Compression for you. Hope this Helps. I am here if you Require more Assistance. Let me know what Happens, Please. Thanks.

 Good Luck

 Respectfully

 John