qualcast powertrak 34 - control box spring lever?

I mowed over the cable on my old but still working well qualcast powertrak 34 and thought I could cut off the end by removing the handle. However, it's a sealed unit, so I bought and fitted a cable joiner. I've refit the handle but cannot work out where the small metal 'control box spring lever' goes and do not know if it is essential for safety or efficiency - the mower blade turns as normal (I've not tried it 'for real' in case there's a safety issue). Anyone know where the lever goes or of a link to a diagram, as I cannot find one on the web? Thanks.