Lose pressure in system ... That reason pump try to restore it bu turn in ... System dont hold it so it turn again . K3 series are expendables. Quality karcher start with k5 which is worth to restore. Service, but fixing k3 might be as expansible as buy new one k3.. But if You hav a time and willingness to do it if sealing gaskets only is damaged You might restore it.

Try replacing the o ring in the lance

Replace the capacitor instead of the compressor.

I soon realized the problem by putting a needle in that small hole where the water comes out: I couldn't because it was clogged. So I disassembled the nozzle and cleaned that small hole. Problem solved.

Very often it's a gasket needs replacement, what's happening is it very slightly losses pressure so the pump kicks in, you can buy gasket kits for them but take the plastic covers of first to make sure there's no cracks in the pressure housing if there is just buy a new pressure washer

Problem rozwiązany?

Low input water flow. Try it with more pressure.

Unbolt and put the nose in vinegar for 1 day..