This single/twin lever engine control is mainly used for yachts, fishing boats and other water vehicles throttle and gear control, using a single handle to achieve control of the throttle and gear. 
The neutral position is done by pulling out the hand levers 30 degree.
Open the throttle step as follows:
1. Remove the lever.
2. Unlock the throttle and pull the flexible shaft.
3. Remove the swivel bracket.
4. Loosen the two (2) hex head screws at the link mechanism and remove the linkage. Make sure that the shift arm engagement teeth position is not changed.
5. Push the throttle arm toward the housing and rotate it 180 degrees until it bounces back. 
6. Use the hex head screw to fasten the connecting rod mechanism to the desired position.
7. Insert the swivel bracket into the appropriate hole.
8. Re-install the push-pull flexible shaft and handle bar.

Features & Details:
double lever double engine control
Pull-out handle disengages shift for throttle only warm-up
Dual action, throttle and shift in one lever
Operate both throttle and shift for 1 engine
Smooth shitting and throttling
Built-in friction to avoid throttle creep
For use with all 33C style and other engine control cables
It works on all types of boat with outboard, inboa