Petrol mower cuts out after a few minutes of running. Also engine misses and pops gently. I've cleaned out the brass screw jet and the primer housing body and removed some gunge from inside primer housing body, but makes no difference. Any suggestions, thanks.
It sounds like fuel starvation. Check the supply right from the tank and make sure that the gunge you discovered isn't lodged anywhere else , in filters for example, or hasn't re-appeared in the carburettor