Goos point Muc, if its stuck in forward and you cannot get it back into neutral, then find the slave solenoid on top the motor.
On the two large terminals on top jump across the two terminals for a second while someone is keeping pressure on the throttle handle. When the motor starts to crank over the handle should go back into neutral.
That is if you have a slave solenoid and this is not a 496 with a relay