The mower only stays running if I keep pressing the prime button I've clean out the carb and put fresh petrol in and cleaned up the spark plug? Any ideas ??
If your carb has a fuel bowl attached to the carb, check the float valve inside, making sure the needle and rubber valve seat that is attached to the float is clear.
Rupert, April 2020
I had the same problem some time ago and it was the diaphragm in the carburetor that was perforated
