Qualcast Self Propelled Petrol Mower With Briggs &stratton 550 Series Motor

Qualcast self propelled petrol mower with Briggs Stratton 550 series motor . Condition is used. Mower has been fine all year but tried starting this week and it starts and runs for about 20 seconds then cuts out. I am not an expert but fuel is the issue probably blocked pipe easy fix for someone who knows. This is self propelled with a super power unit with briggs and Stratton 550 series motor 158cc. This is not your entry level £130 mower this was over £250