Chrysler 20 and 30 HP Outboard Motors Service Manual OB 3435, Page 43Get this manual
discharging into the throttle bore through the primary idle discharge portFigure 2 Figure 3Intermediate Operation
Figure 2Idle Operation
Intermediate OperationDuring intermediate operationthe engine speed and air flow increases as the throttle shutter opens As this occurs, the secondary idle discharge ports are progressively exposed to engine suction which withdraws fuel from the main nozzle well through the idle tube into the by- pass chamber and discharging into the engine Continued throttle opening increases the carburetor air flow and suction in the main nozzle which also lifts fuel from the nozzle well into the air stream The open position of the throttle determines the quantity of intermediate fuel being delivered from the main nozzle which mixes downstream with the existing intermediate and idle fuel al ready flowing in the systemFigure 3High Speed OperationAs the throttle opening is increased to obtain high speed operation, suction at the main nozzle also increases, lifting greater quantities of fuel from the nozzle wellAs this occursthe fuel level within the nozzle well tends to lowerAs the fuel continues to lower in the fuel wellyou will note that the bottom end of the idle tube will eventually become exposed to incoming carburetor air through the main nozzle air bleed located in the choke boreWhen this level is reachedthe idletube is no longer in solid fueland the intermediate fuel