Why does my karcher powerwasher starts and dies after 2 minutes

No fuel... carburetor float/needle valve is likely stuck shut. Clean carburetor bowl and use a fuel treatment such as Seafoam, per directions.

You did winterize the machine? Leaving water in a powerwasher will freeze and damage the pump. It's a common happening, because people don't think of it or are not told by the maker.

Is your air filter dirty? If so replace it. If it is still doing the same thing try this:

Turn off the fuel valve, or drain the gas tank, then place a rag under the bowl to catch the gas that will run out (the bowl is under the carburetor). Loosen the "nut" that holds the bowl on, and after the gas has stopped draining remove the nut and bowl. Blow out with compressed air, if available. Put the bowl back on and try to start it. If it still will not run off choke, the carburetor probably needs a good soaking or to be replaced.

http://scripts.karcher.com/scripts2008/bta/document/BTA-59612160-EN.pdf

user manul and troubleshooting tips

I am going to suggest a tune of of the engine. Change the oil and oil filter. Check the air filter is clean and replace it if it isn't. A new spark plug.

Did you try a new spark plug. Old one may have fouled.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/craig_3fa289bf857b1a3c

Remove and clean the carburator. Sound line a stuck needle on the float. 

Look for +/- on knob and turn + direction for max pressure.

I had the same problem 3 years old, maybe used 10 times - removed the air filter and the washer started fine. The air filter looked fine - I have not tried to replace it or figure out the root cause. I was just happy to get it running again :)

I had same problem won't build pressure. go to http://www.wmpcs.com/index.php?main_page=page&id=14 and see diagram. I pulled white plastic cover off top of pump (2 torx screws), remove main pump from gas motor otherwise you wont be able to get at the valve below. The important part is the valve below the the white plastic piece, it has a raised slot and mine was stuck in there. I used needle nose pinched together with pliers to lift it straight up. After wd40 and cleaning the hole and valve it should pop in and out easy. Put everything back mine worked like a charm after that. So at least I know what the problem is. Great powerwasher-I use for house painting part time and love it.