Small Engines (Lawn Mowers, etc.): McCulloch chain saw, coil pack, fuel flow

Question
After putting on new fuel lines and primer, testing for good spark, blowing carb passages out, throttle and choke butterflys move freely, fresh gas/oil mix, compression test (thumb method), the saw starts and runs for a while. Runs long enough to open the choke.  Runs a while longer, then dies.  Coil pack going?  Other ideas? Thanks a lot.  

Answer
Hi Larry,

You will need to determine if the problem is a lack of spark or a lack of fuel flow.  Right after it quits, remove the spark plug, reconnect the wire and lay it against the engine head.  Pull the engine over and watch for spark at the plug's electrode.  If no spark, it could be the coil or kill switch.

If good, then try to start while squirting fuel or starting fluid into the carb intake.  If it starts, then the carb most likely has dirt, debris, gummed fuel or water inside.  You will need to remove the carb, disassemble it, clean all the small internal openings and blow it out with compressed air.   Probe each and every hole with a small wire.  A carb rebuild kit wouldn't hurt either.

Let me know how you make out.
Michael