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TROUBLESHOOTING & REPAIR
ENGINE THROTTLE ADJUSTMENT TEST (continued)
6.If either of the readings is incorrect, adjust the throttle as follows:
Adjust HIGH IDLE: Use the 8mm wrench to loosen the locking nut. See Figure F.8 for location of the adjusting screw and locking nut. Avoid breaking the seal. There should be enough play to allow adjustment without disturbing the seal. Turn the threaded screw
Adjust LOW IDLE: First make sure there is no load on the machine. Set the IDLE switch to AUTO and wait for the engine to change to low idle speed.
Use the 7/16" wrench to loosen the solenoid lever arm locking nut. See Figure F.9. Adjust the threaded solenoid lever arm shaft, to change the amount of throw in the lever arm, until the tach reads between 1350 and 1400 RPM. Retighten the locking nut.
Frequency Counter Method
1.Plug the frequency counter into one of the 115 VAC auxiliary receptacles.
2.Start the engine and check the frequency counter. At HIGH IDLE (1800 RPM), the counter should read 60 Hz. At LOW IDLE (1400 RPM), the counter should read 47 Hz. Note that these are median measurements; hertz readings may vary slightly above or below.
3.If either of the readings is incorrect, adjust the throttle as follows:
Adjust HIGH IDLE: Use the 8mm wrench to loosen the locking nut. See Figure F.8 for location of the adjusting screw and locking nut. Avoid breaking the seal. There should be enough play to allow adjustment without disturbing the seal. Turn the threaded screw
Adjust LOW IDLE: First make sure there is no load on the machine. Set the IDLE switch to AUTO and wait for the engine to change to low idle speed. Use the 7/16" wrench to loosen the solenoid lever arm locking nut. See Figure F.9. Adjust the threaded solenoid lever arm shaft, to change the amount of throw in the lever arm, until the frequency reads 47 Hz. Retighten the locking nut.
Oscilloscope Method
1.Connect the oscilloscope to the 115 VAC receptacle, according to the manufacturer’s instructions. At HIGH IDLE (1800 RPM), the waveform should exhibit a period of 16.6 milliseconds. At LOW IDLE (1400 RPM), the waveform should exhibit a period of 21.4 milliseconds. Refer to the NORMAL OPEN
CIRCUIT VOLTAGE WAVEFORM (115 VAC SUPPLY) HIGH IDLE - NO LOAD in this section of the manual.
2.If either of these periods is incorrect, adjust the throttle as follows:
Adjust HIGH IDLE: Use the 8mm wrench to loosen the locking nut. See Figure F.8 for location of the adjusting screw and locking nut. Avoid breaking the seal. There should be enough play to allow adjustment without disturbing the seal. Turn the threaded screw
Adjust LOW IDLE: First make sure there is no load on the machine. Set the IDLE switch to AUTO and wait for the engine to change to low idle speed. Use the 7/16" wrench to loosen the solenoid lever arm locking nut. See Figure F.9. Adjust the threaded solenoid lever arm shaft, to change the amount of throw in the lever arm, until the period is 21.4 milliseconds. Retighten the locking nut.