most computer radios have a throtle cut which just goes to low throtle trim. You set the throtle to the idle you want at neutral trim and then to cut stop the engine just pull the trim lever all the way down or hit the throtle cut, which does the same thing. Usauly radios with digital trims will have a throtle cut button which simply overrides the trim and pulls the throtle all the way down to close the opening and shut the engine off.