"LOAD STOP ADJ" - Load stop adjustment. Limit of the governor output at a rated engine speed
"THROT STOP ADJ" - An approximation of the high idle setting on the engine
"FRC ADJ" - Adjustment for the fuel ratio control (The FRC setting is regulated by emission laws)
"LOW IDLE ADJ" - Low idle adjustment
"FUNC CHECK #1" - Output of the governor at low idle and at high idle with the throttle stop backed out.
"FUNC CHECK #2" - Rated output of the governor after setting the throttle stop
"FUNC CHECK #3" - Rated output at Peak Torque (verifies proper torque cam)
"FUNC CHECK #4" - Low idle lug absolute output value
"FUNC CHECK #5" - Low idle lug change in output
Note: The preload dimension that is stated in the technical marketing information (TMI) should only be used as a reference. The manufacturer of the governor is not required to meet the specification. The number of governor spring shims is determined by the governor test bench calibration. Governor spring shims are added in order to increase the tension on the high idle screw. Governor spring shims are removed in order to meet the function of low idle lug specification. If you are rebuilding the governor, the reference for the governor spring preload dimension is a good starting point.
The following procedures are used to functionally check a governor without removing the cover lug or the seal from the throttle stop. This "check" is intended as an aid to determine if a governor is functioning correctly.
Use the following procedure if an engine performance complaint occurs and the suspected cause is the governor. The Testing and Adjusting, "Governor (Type) - Adjust" procedure would be used if the governor did not pass the Testing and Adjusting, "Governor (Type) - Check" procedure.
- Install the governor on the calibration bench. Refer to the Testing and Adjusting, "Installation Of Governor On 1U-7326 Governor Calibration Bench " section in this manual.
- Connect the test bench to an electrical outlet. Turn the tachometer ON.
- Turn the switch on the test bench to the ON position.
- Turn the control knob for the governor speed counterclockwise to the slowest speed. Inspect all of the fluid connections for leakage. Perform any necessary repairs.
Note: Always approach a specified rpm setting from a minimum of 100 rpm above the rpm that is required. This will ensure that the test readings are consistent for the entire test procedure.
All specifications for the governor adjustment procedure are in the Technical Marketing Information (TMI). If you are checking a previously adjusted governor, the tolerance (±) factor should be doubled. The tolerance factor should be referred to as an expanded tolerance.
As an example, if a tolerance in the specifications is listed as ± 0.05 mm (± 0.0020 inch), then the expanded tolerance for this checking procedure would be increased to ± 0.10 mm (± 0.0039 inch). This expanded tolerance will not be listed in the specifications. The tolerance must be calculated by the operator of the governor calibration bench.
| NOTICE |
|---|
Do not turn the speed control knob unless the test bench is running. Damage to the variable speed drive may result. Except in the event of an emergency, the speed control knob should always be returned to the slowest rpm setting before the calibration bench is turned off. |
- If the governor is equipped with a fuel ratio control (FRC), connect a regulated air supply (a hand pump or a squeeze pump) to the fuel ratio control.
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| Illustration 1 | g00657715 |
(1) Fuel ratio control (2) Throttle stop adjustment screw | |
- Adjust the speed of the calibration bench to the specified load stop rpm. Slowly move the throttle to the low idle position. Slowly move the throttle back to the throttle stop. Do not move the throttle again during this checking procedure.
| NOTICE |
|---|
A regulated air supply of 140 to 210 kPa (20 to 30 psi) must be used to avoid damage to the fuel ratio control. |
- The output dimension should be within the expanded tolerance dimension in "FUNC CHECK #2" of the TMI data.
- Ensure that the air pressure that is going to the fuel ratio control is turned OFF. Any air pressure that may have inadvertently been applied to the fuel ratio control must be removed. Disconnect the air supply hose, if necessary, in order to purge any air that may be trapped in the line.
Note: If the governor is not equipped with a fuel ratio control, proceed to Step 11. For those governors that contain a fuel ratio control, continue with Step 8.
- Adjust the speed of the calibration bench to the specified rpm for the fuel ratio control.
- Apply regulated air pressure to the fuel ratio control for approximately three seconds. Purge the air pressure. Rotate the throttle lever from the throttle stop to the low idle position and hold the throttle at low idle for approximately three seconds. Return the lever to the full throttle position. The output dimension should be within the expanded tolerance band for the specified dimension of the fuel ratio control.
- Adjust the speed of the calibration bench to the rpm that is specified in "FUNC CHECK #3". The output dimension should be within the expanded tolerance dimension.
Note: For the remainder of the test, the air supply to the fuel ratio control must be on.
- Adjust the speed of the calibration bench to the specified "THROT STOP ADJ" rpm that is specified in the TMI. Wait for one minute in order for the output dimension to be within the expanded tolerance dimension for "THROT STOP ADJ". If the output dimension is still changing, you may need to wait longer.
The governor is operating correctly and the governor can be used again without any adjustment if the performance of the governor is acceptable according to the tolerance checks. If the governor fails the fuel ratio control dimension check, the dimension can be reset and the governor can still be used without any further adjustments. Refer to the Testing and Adjusting, "Governor (Type) - Adjust" section in this manual. If an adjustment is made, the standard specification tolerance is applicable and the expanded tolerance is not applicable.
If the governor fails any of the other dimension checks, proceed with Step 13.
- It may be necessary to adjust throttle stop adjustment screw (2) during the factory dynamometer load testing in order to provide the correct engine "FULL LOAD RPM". This is due to slight variations in other engine components. The throttle stop adjustment may be correct for a particular engine, except when the governor is tested separately. The governor may be outside of the expanded tolerance for the "THROT STOP ADJ" that is specified in the TMI. Refer to Step 15 for additional information on the "THROT STOP ADJ".
The output dimension that is checked in Step 12 is considered to be the correct dimension when the following conditions exist:
- The governor that was tested must be installed on the original engine.
- The governor must have the original lockwire and tamper resistant seal that is fastened to the throttle stop.
- The engine must still have the same fuel injectors and the same fuel setting dimension.
If the governor meets all three of the above conditions, use the following procedure to check the functions of the governor. Begin with Step 14. In all other instances, use the settings that are specified in the TMI. Other settings will have an unknown effect on the performance of the governor.
- The governor that was tested must be installed on the original engine.
- Increase the speed of the calibration bench until the output dimension goes to zero. Decrease the speed on the calibration bench until the output dimension is less than the throttle stop output dimension by 1 mm (0.039 inch).
Wait until the output dimension is stabilized.
- Slowly reduce the speed on the calibration bench until the output dimension for the "THROT STOP ADJ" that is specified in the TMI is reached. Wait until the reading stabilizes. The throttle stop output dimension speed may be higher or lower than the specified rpm. Record the throttle stop output dimension speed. This rpm should be within ± 100 rpm of the specified "THROT STOP RPM".
Note: If the speed that was recorded is within the ± 100 rpm, proceed to Step 16. If the speed that was recorded is not within the ± 100 rpm, the governor should be completely readjusted. Refer to the Testing and Adjusting, "Governor (Type) - Adjust" procedure in this manual.
- Remove the lockwire and the tamper resistant seal on the throttle stop adjustment screw. Turn the throttle stop adjustment screw counterclockwise.
- Adjust the speed of the calibration bench to the specified "LOAD STOP ADJ" rpm. The output dimension should be within the expanded tolerance.
If the output dimension for the "LOAD STOP ADJ" is correct and the governor meets the requirements that were established in Step 13, perform Step 18.
If the governor does not meet these requirements, the adjustment procedure should be performed again. Refer to the Testing and Adjusting, "Governor (Type) - Adjust" section in this manual.
- Adjust the speed of the calibration bench to the speed that was recorded in Step 15 of this procedure. Adjust throttle stop adjustment screw (2) in order to obtain the specified throttle stop output dimension.
Tighten the locknut on the adjustment screw. Check the output dimension again.
- Increase the speed of the calibration bench by at least 100 rpm. Reduce the speed of the calibration bench back to the speed that was recorded in Step 15 of this procedure. Check the throttle stop output dimension again.
If the dimension is not within expanded tolerance, perform Step 18 again.
- Reduce the speed of the calibration bench to the lowest setting. Turn the switch to the OFF position. The tachometer will turn off automatically after a short period of time.
- After the governor has been installed on the engine and the low idle speed has been adjusted, seal the throttle adjustment screw with the lockwire and the tamper resistant seal.