Hayter Harrier 48 Self-propelled Lawnmower Spares Or Repair

This mower has damage to front edge of the body but it is cosmetic as there is a guard for the blade underneath.The grass bag is taped up but is usable for now.The engine starts but will not keep running,or sometimes will run at idle for ages but not rev up.I have tried most things and in desperation last week I swapped the carburetor from my other mower onto this one.The engine ran lovely and I cut my 2 lawns with the Hayter,she runs well and is smooth and quiet,the power drive is all working perfectly and she made some nice stripes with the rear roller.So I am pretty sure a new carb is the permanent cure.I have tried cleaning it out but it didn t fix it .The engine is a Briggs and Stratton Quantum.Item is collection only,any questions please ask,no stopping auction,no buy it now.Thanks.