I think with that setup you're just begging to have your servo shaken to bits and possible have the mount fail in flight. That cantilevered mount is going to actually amplify the vibrations from your engine, which is already going to be pretty bad because you're mounting it to the engine mount of a 4 stroke. It will be better to go the traditional route and put the servo somewhere behind the firewall and drill a hole for a tube to go out to the throttle.