I have taken my lawnmower to the company for repairs. I described the fault to the service agent. The lawnmower drips petrol/oil out of the carburetor through the airfilter, and the spark plug must be cleaned weakly before use due to oil residue between the air gap.
I received the quote, only replacing the spark plug, air filter and cutting blade. Obviously I queried the quote since this did not address the problem. But I was told it might be that I am not operating the lawnmower incorrectly with the choke fully open. Even though I operated it correctly for about two years, it seems I suddenly started to use the lawnmower incorrectly during the last few weeks only.
I got my lawnmower back yesterday, today I cut a piece of lawn, roughly 30m2 in size, and the lawnmower leaked oil/petrol out of the carburettor. Problem not fixed.