Portable Generator User Manual
PAGE 34 —MQP20P STANDBY GENERATOR • OPERATION AND PARTS MANUAL — REV. #1 (11/28/11) 
MAINTENANCE
FLUSHING  OUT  RADIATOR  AND  REPLACING 
COOLANT
1.  Remove radiator cap. Remove the coolant drain plug. 
Move the lever to the open position to start draining 
out coolant. See Figure 25.
Figure 25. Draining Coolant
2.  Flush the radiator by running clean tap water through 
radiator until signs of rust and dirt  are removed. Do 
not  clean  radiator core  with  any  objects, such  as  a 
screwdriver.
3.  Check hoses for softening and kinks. Check clamps 
for signs of leakage.
4.  Move lever to the closed position and reinstall coolant 
drain plug.
5.  Replace with coolant as recommended by the engine 
manufacturer.
6.  Close radiator cap tightly.
Turn to
Open
Radiator
Remove
Radiator Cap
Radiator
Drain
Battery
Charger
Remove
Drain Plug
 WARNING
Allow engine to  cool before flushing  out 
radiator.  Flushing  the  radiator  while  hot 
could cause serious burns from water or 
steam.
RADIATOR CLEANING 
The radiator (Figure 26) should be cleaned with a high-
pressure washer when excessive amounts of dirt and debris 
have accumulated on the cooling fins or tube. When using 
a high pressure washer, stand at least 5 feet (1.5 meters) 
away from the radiator to prevent damage to the fins and 
tube.
Figure 26. Radiator Cleaning
VOLTAGE REGULATOR ADJUSTMENTS
When the voltage regulator is defective or broken and is 
replaced, the following adjustment procedure needs to be 
performed on the newly installed voltage regulator.
Potentiometers
Figure 27 shows the screwdriver adjustable potentiometers 
on the front of the voltage regulator.
Figure 27. Voltage Regulator Potentiometers
1.  Coarse Voltage Adjust — A screwdriver adjustable 
potentiometer  on  the  front  of  the  voltage  regulator 
VOLTAGE REGULATOR
VOLT
STAB
U/F
1
2
3










