Small Engines (Lawn Mowers, etc.): poulan 2450 chainsaw, cold crank, leak down test

Question
QUESTION: chainsaw starts and runs fine until it reaches operating temp, then dies, whether at idle or when given throttle. whats up?

ANSWER: Have you replaced the spark plug?  What is the compression when the engine is warm?  Has the carburetor ever been rebuilt?  Have you performed a leak down test to see if a gasket or seal may be leaking when the engine is warm?

I am more concerned with the compression.  Take a reading with the engine cold and the engine warm.  Let me know what the compression is.
Eric

---------- FOLLOW-UP ----------

QUESTION:  spark plug looks fine. cold crank compression 145, warm 135 (did'nt seem to reach full operating temp before it died)

         bwana

Answer
I have had problems with bad plugs.  Try a new one.  The compression should be fine.  
Does the saw start easy?  Is the muffler spark arrestor screen or muffler port clogged with carbon?
Try a new plug and let me know the other answers to the questions.
Eric