Maybe it will help if I refer to the drawing,
https://lookup2.toro.com/Ill/1x/375/375100.gif. Part No. 923 has two
ears, one attached to the brake handle cable the other is spring
tensioned. When I release the brake handle the cable definitely
slackens and releases it's ear sufficiently, but I have to reach down
and manually squeeze these two ears together to kill the engine. Must
be something obstructing the opposite side of the ear inside the engine.