Yep, it's a 10 cubic inch 158cc Briggs and Stratton Quattro 40.
Firstly, remove the cowl and clean all the grass etc under there, sometimes it impedes the governor function. After you've done that start her up and adjust the governor setting by bending the tabs, where the springs are anchored to, in or out to increase/decrease engine speed. The large spring controls high speed RPM while the small spring generally controls the idle speed.
Don't worry too much about the mangled larger spring, you can cut those coils off and and bend out a new coil to anchor to the bendable tab.
Let us know how you go.
Cheers, Ted
