Chainsaws

Danny,

This is sort of an  interesting problem, and I can't figure out why three different Dealers couldn't solve and fix the problem.

OK - Listing the things that you have already tried, here are some of the things that I would check and test. After running the chainsaw, and when your in that 5-10 minute window, after the engine is shutdown and won't start. I would pull the spark plug, and see if it looks Wet or Dry. Be careful the plug will still be Hot, I also assume that you have tried a brand new spark plug ? Anyhow, after you have removed the spark plug & inspected it, then spray either a small quantity of fuel mixture into the cylinder Or you can use "Blaster" small engine tune-up spray, (note: this contains oil & fuel & a carbon cleaning agent). "DO NOT Use straight gas, or Carb cleaner spray which has No oil additive". Then put the plug back in and see if it starts, within that 5-10 minute window. If it starts then you have a fuel problem, after the engine shuts down and that is where I would start diagnosing and troubleshooting. 

It is possible you have a fuel line problem to the carburetor, I know you stated you replaced the carburetor, but did you replace the fuel line & fuel filter ? A small split or break in the fuel line may give you a similar symptom where the carburetor is losing its prime from an air leak. Its easy to replace the fuel line & filter, so I would definitely try that first.

Next, assuming the carburetor has fuel, and its not draining back down in the fuel line, You need to check that you are pulling air or suction thru the Venturi of the Carburetor. An air leak in either the engine or the induction intake boot or engine seals between the carburetor an engine will cause a similar problem. A couple simple tests that can be performed with a cold engine to determine the condition of the engine. ( Note:A  Compression gauge & Pressure/ Vacuum gauge would be helpful to better test the engine), However you can try the following: Remove the air filter & filter holder and press your thumb over the carburetor, with the choke wide open  & throttle wide open, pull on the starter cord, can you feel a vacuum pressure be created by the engine ? If you can't feel a vacuum at the intake to the carburetor, you may have a bad intake boot seal. This test would be much more effective with the proper gauges and doing an engine vacuum/pressure test to check the intake boot too. 

I hope this little bit of a primer, may help you find or locate your problem, small leaks are sometimes difficult to find, and may be easier to do component replacements like replacing the fuel line, or replace the induction intake boot.

If you need additional help, Please let me know

Karla

PS. I am Not a Husqvarna Representative or Repair service just an experimental chainsaw person