0320015 JOHNSON ORIFICE, Idle rstr. (#33)

Mechanical Governor Adjustments
Low Idle and High Idle Adjustment
Start the engine and run until normal operating temperature is reached. Check the low idle and the high idle rpm with no load on the engine. If an adjustment is necessary, use the following procedure:
Illustration 1 g00676733
Mechanical governor
(1) Cover
(2) Adjustment screw
Remove cover (1) from the top of the governor's housing.
Turn adjustment screw (2) in order to change the high idle rpm.
Move the governor lever in order to change the rpm of the engine.
Move the governor lever back to the original position.
If necessary, repeat Step 2 through Step 4.
When the correct high idle speed is obtained, install cover (1).
If necessary, adjust the low idle rpm. To adjust the low idle rpm, adjust the throttle linkage. Refer to Testing and adjusting, "Carburetor - Adjust". Woodward PSG Governor Adjustments
Perform the following procedures after the linkage for the governor has been adjusted. Refer to Specifications, "Governor Linkage".Initial Operation
Perform the following procedure for a new governor or for a governor that has been serviced:
Illustration 2 g00677571
Electric Woodward PSG Governor
(1) Knob
(2) Compensating valve
Start the engine and allow the engine to run until normal operating temperature is achieved.
Adjust the engine speed, if necessary. If you have an electric governor, use the remote control and the motor for the speed adjustment.If you have a nonelectric governor, turn knob (1) or turn the adjusting screw.
Open compensating valve (2) for one to two turns. The engine will hunt. Allow the engine to run for about 1/2 minute while the valve is open. This will allow air to be purged out of the governor's oil passages.
Gradually close compensating valve (2) until the hunting stops. Note: Do not close the valve too far. This could cause the governor to react slowly after a load change.Adjusting the High Idle Stop
Start the engine. Run the engine until normal operating temperature is achieved.
Illustration 3 g00745188
Typical nonelectric PSG governor
(1) Stop screw
(2) Adjusting screw
Loosen the locknut for stop screw (1). Turn the stop screw counterclockwise for approximately two turns.
With the stop screw in this position, the engine can overspeed. This can cause damage to the engine components. Be ready to shutdown the engine if it has an overspeed condition.
Adjust the engine to the desired high idle rpm. If you have an electric governor, use the remote control and the motor for the speed adjustment.If you have a nonelectric governor, turn the knob or turn adjusting screw (1).
After the desired high idle rpm is reached, turn stop screw (1) clockwise until the screw stops. Tighten the locknut. Observe the engine rpm on the tachometer. If the engine speed is still correct, the adjustment is correct.Checking the Speed Droop
This engine has adjustable speed droop. The adjustable speed droop is between zero and seven percent. This amount will be different for different applications. This percent of adjustable speed droop is the percent between the high idle speed (no load) and the engine full load speed. In order to calculate the adjustable speed droop, use the equation in Table 1.
Table 1
Equation for Calculating the Percent of Speed Droop
H − F × 100 = % Droop
F
H is the high idle rpm.
F is the full load rpm.
Multiply the full load speed by the desired adjustable speed droop. Add the number from this multiplication to the full load speed. This will calculate the speed at no load (high idle rpm).
Start the engine. Run the engine until normal operating temperature is achieved.
Operate the engine at high idle rpm. Observe the tachometer.
Connect a known load to the engine. The load must be less than the full load for the engine. Observe the tachometer. Record the amount of decrease in engine speed.
Determine the ratio between the load that is on the engine and the engine's rated load. The ratio must be equal to the ratio of the decrease in engine speed. See Table 2.
Table 2
Ratio for Verifying the Speed Droop
Known load = Decrease in engine rpm from Step 4
Rated load Droop from Step 1
Table 3
Example of the Ratio for Verifying the Speed Droop
105 kW = 27 rpm
210 kW 54 rpm
If the ratios are not equal, an adjustment is necessary. Remove the load and stop the engine. If the engine speed has decreased too much, the speed droop must be decreased. If the engine speed did not decrease enough, increase the amount of speed droop.Adjusting the Speed Droop
Illustration 4 g00743802
(1) Bracket
(2) Set screw
(3) Lever
(4) Stop screw