Chainsaw Repair

Hello:

I have an approximately 10 year old Echo CS345 #03020360.  A few weeks ago, I tried to use it for the first time in about 2 months.  It had been borrowed and still had fuel in the tank.  (I trusted the borrower not to do that.)  Anyway, the starter cord is VERY hard to pull. I removed the spark plug and the starter cord pulls very easily.

I removed the muffler and checked the exhaust.  It was clear.  With the muffler off, it is still VERY hard to pull with plug in, very easy with plug out.  The plug is an E3.12 from Lowe's which is a replacement for a Champ. CJ6Y which the manual lists as an acceptable replacement.

I sprayed WD40 directly into the engine exhaust port and let it sit overnight.  When I replaced the plug, the starter pull was still VERY hard.  I would not want to try starting the saw with the starter cord being that hard to pull.  With the plug removed, it is still very easy to pull. 

I don't know what else to try and would appreciate any help.

Thanks