18″ Rover Push Lawnmower With Briggs & Stratton Petrol Engine Runs Only Hi Revs

18 Rover Push Lawnmower With Briggs Stratton Petrol Engine Runs But Only Hi Revs Does not seem to make any difference when throttle is moved I presume carb fault Sold as not working in need of repairs NO RETURNS But do not have time to strip Collection only