This husqvarna mower that I had for about 4 years quit on me today. I checked the air filter, cleaned carburetor, and replaced the spark plug. It�ll crank on, but die within a few secs. Makes blue smoke while running too.

When I checked the air filter, one side was heavily stained with oil.
I�ve never seen something like that before.
What happened?

I�m worried that oil stained air filter means a gasket failed and will require total rebuild.

You put your mixed 2 cycle gas in on accident?

Nope.
Thinking I should replace the carburetor

did you have it tilted on it's side for a bit?

Mine did the same thing when the ethanol fuel gummed up. Would run a bit and then die.

run a half tank of seafoam through it

my husquarvarna only lasted 5 yrs, the last year was a beating, I tied the spring on the throttle with some fishing line, this increased my idle speed to keep it running. I cleaned the carb, new filter and plugs, always working on it. got a new honda this year

Maybe it ain't got no gas in it...........

My lawn mower was being stupid today so I went and bought a new one. It was time to put the old one out of its misery.

Replace carb

I had this happen with a Briggs. I couldn't mow on any kind of sideways slope, or it would smoke and choke down. I now have a Husqvarna with a Honda engine, and think it would probably mow upside down.

Drain the oil, dump the fuel, clean the air filter, refill the oil, put fresh fuel with Seafoam in it, put the clean air filter on it. Start it and run it hard if possible.

If it is still smoking, the Piston rings are probably shot.

Make sure the gas cap is venting. Just loosen it and see if it keeps running.

Clean the holes out on the main jet. Probably has green corrosion on it from bad gas.

I'll give you tree fiddy