Why did King want an election called?

He wanted to win the Liberals.

Explanation:

Mackenzie King having been elected by the minority in 1921 called the election so can win more of the liberals at his time. He never got that since the conservatives won 116 seats  ahead of liberals with 101 seats. He remained in power despite his loss and retained his presence from progressives with 24 seats. The liberals were involved in scandals that resulted in availing for the statue of Westminster in 1931 and making room for Canada's independence and making the role of Governor-General a  figure-head and representative of the government and political will and power resting on the Prime Minister.