A marine propulsion outboard or stern drive includes a motor driven, hydraulic shift mechanism. A DC motor includes the conventional separate reverse winding and forward winding, each of which is connected individually in series with the motor armature to a battery through motor driven limit switches to stop at neutral, forward or reverse drive positions. The armature is connected to drive a valve for actuating a hydraulic shift unit. A resistor and a diode is connected in parallel between the power side of each winding and ground. The resistor acts as an electrical load and eliminates hunting of the drive system and the repeated operation of the limit switches. The resistors employed are relatively low wattage type so as to burn open in a relatively short period and without a flame or mass heat characteristic capable of igniting fuel fumes associated with recreational type marine propulsion devices. The diodes are back biased by the battery polarity but conduct transient voltages of the opposite polarity which may arise in the motor circuit.
A shift operation apparatus for an outboard motor of the present invention comprises a case fixed to an outboard motor, a motor provide at the case, a worm gear which is rotated by the motor, a worm wheel engages with the worm gear, an output shaft provided so as to freely rotate, a gear mechanism which transmits rotation of the worm wheel to the output shaft, an output arm which is attached to the output shaft, and which moves a range from a shift forward position to a shift reverse position with a neutral position being a boundary, a sensor which outputs a signal relating to a shift position of the output arm to a control circuit, and a force transmitting member whose one end is connected to the output arm, and whose other end is connected to a portion to be operated of a shift mechanism.
An actuator of a marine propulsion transmission is attached to a movable clutch member through the use of a coupler which comprises a generally spherical member formed as a portion of the actuator and a chuck device formed as part of the clutch member. The generally spherical member, or alternatively shaped component, is received by the chuck device and retained therein. The components are configured to allow relative rotation between the actuator and the clutch member while causing them to move axially in synchrony with each other.
Ignition pulses derived from an engine ignition coil primary are fed to the input of an ignition interruption circuit that employs an integrated circuit timer. The state of the output terminal of the timer is governed by an RC time constant circuit and by trigger signals supplied by a trigger circuit in response to occurrence of each ignition pulse. The timer output is coupled to the gate of an SCR which when it receives gate current as a result of the timer output being in a high state becomes conductive and bypasses ignition pulses to ground to thereby lower engine rpm to a preset minimum in which case gate current is removed and at least enough ignition pulses are allowed to be unbypassed for keeping the engine running above stalling speed. The timer, in effect, compares the interval between pulses with its time constant. When the intervals are longer than the time constant period the timer output remains low and provides no gate current, but when the opposite condition exists gate current is supplied until the intervals between ignition pulses equal or exceed the time constant period.
