 By 1882, the scoop wheels had reached the practical limits of improvement, and the Commissioners asked George Carmichael to act as a consulting engineer, and advise on how centrifugal pumps could be utilised.Carmichael recommended a new engine and pump, and an engine was obtained from Hathorn Davey and Co., which would drive a horizontally mounted centrifugal pump of diameter.Completion of the Lark Engine installation was delayed by failure to achieve the quoted output, and by flood levels affecting the construction of the outfall tunnel, but the problems were resolved by November 1883, and the Commissioners were able to delay taking a decision on the Brandon Engine because of the efficiency of the new engine.