Chainsaws

Arlene,

First, If its under warranty then I would definitely take it to an authorized Husqvarna repair center, But if you choose to troubleshoot it yourself, here are some suggestions:

I think I would start with a simple tune-up, and replace the fuel filter, the air filter, and the spark plug (making sure the gap is set correctly). My first guess would be it could be a simple spark plug problem. If the saw starts properly I would also check that the carburator is not set too rich or too lean, and if you have access to a two cycle digital tach, I would also check the idle, clutch, and full throttle speeds.

Oh, I am also assuming your using the proper fuel to fuel oil ratio mix in your engine per your instruction manual, most new engines are a 50:1 mix. Not putting oil in with the fuel per the correct ratio will definitely cause some problems with a hot engine, and even potentially sieze the piston in the cylinder.

It is possible your also simply flooding the engine when re-starting a hot engine, check your owners manual for specific instructions on how to start a Hot engine. Most hot engine re-starts require that you don't use the choke, as you would choke a cold engine, so check your instructions.

Next, I would thoroughly check the fuel system, it could be just a coincidence that the engine starts when cold but Not when Hot it might just be a time thing, like waiting the 30 minutes, for example a dirty fuel filter or a little dirt in the carburator may allow fuel to seep into and through the carburator allowing it to start and run but after shutdown, it needs time to seep in again. So anyhow, change the fuel filter in the fuel tank they are reasonable, check the fuel lines that nothing looks like it is partially plugged, or replace the fuel lines if your handy, clean and thorougly inspect the carburator, and if you have a primer bulb make sure the primer bulb is remaining full or almost full of fuel after shutting the saw off. If the primer bulb is emptying after the saw has been running and shutdown than, your problem could be the check valve in the primer bulb, and you will need to replace the primer bulb..

Next, it could be a hot engine which is overheating, and the things I would check would be to remove the muffler and check for carbon build up in the cylinder port, and clean it out, check the spark arrestor for carbon and clean, make sure there is no exhaust blockage.

Finally you could have a bad piston ring or partially stuck ring in the cylinder, you can look at the piston ring through the exhaust port when you remove the muffler, and see if there is any piston scoring or possible ring problem.  There are some chemical spray products available which say if you remove the spark plug, you can spray the "Tune up cleaner" into the engine and follow the directions on the spray can, and it will un-stick rings, that may be worth a try, if not you will need to do an engine compression test and possibly an engine overhaul.

Oh, one other heat related problem is the engine spark or ignition module, It is possible since these are electronic modules that when the ignition module heats up that it stops working, and when it cools down it starts working again but usually if this were occurring, the saw when it lost its ignition would be shutting itself off, and that was not your symptom, but it definitely would stop you from starting, If you know how to check ignition spark, I would try that when you shut the saw off and see if your getting spark when your trying to re-start it.

I think that just about covers any reason why your saw would possibly not start.

I hope this helps!