PROBLEM
Gas engine pulls hard (won't start)
Gas engine does not start
Gas engine doesn't work properly
Gas engine operates, but
displacement pump doesn't operate
Displacement pump operates, but
output is low on upstroke
Displacement pump operates but
output is low on downstroke and/or
on both strokes
Paint leaks and runs over side of
wetcup
Excessive leakage around hydraulic
motor piston rod wiper
Fluid delivery is low
311279F
Troubleshooting
CAUSE
Hydraulic pressure is too high
Switch OFF, low oil, no gasoline
Faulty engine
Pump valve is OFF
Pressure setting too low
Displacement pump outlet filter
(if used) is dirty or clogged
Tip or tip filter (if used) is clogged
Hydraulic fluid too low
Belt worn, broken or off
Hydraulic pump worn or damaged
Dried paint seized paint pump rod
Hydraulic motor not shifting
Piston ball check not seating properly Service piston ball check.
Piston packings worn or damaged
Piston packings worn or damaged
Intake valve ball check not seating
properly
Suction tube air leak
Loose wet-cup
Throat packings worn or damaged
Piston rod seal worn or damaged
Pressure setting too low
Displacement pump outlet filter (if
used) is dirty or clogged
Intake line to pump inlet is not tight
Hydraulic motor is worn or damaged Bring sprayer to Graco distributor
Large pressure drop in fluid hose
SOLUTION
Turn hydraulic pressure knob
counterclockwise to lowest setting
Consult engine manual, supplied
Consult engine manual, supplied
Set pump valve ON
Increase pressure, page 12
Clean the filter
Remove tip and/or filter and clean
Shut off sprayer. Add fluid*
Replace. See manual 311283
Bring sprayer to Graco distributor for
repair
Service pump. See manual 311485
Set pump valve OFF. Turn pressure
down. Turn engine OFF. Pry rod up
or down until hydraulic motor shifts.
Manual 311283
See manual 311485
Replace packings. See manual
311485
Tighten packing nut or replace
packings. See manual 311485
Service intake valve ball check.
See manual 311485
Tighten wet-cup enough to stop
leakage
Replace packings.
See manual 311485
Replace these parts.
See manual 311283
Increase pressure, page 4
Clean filter
Tighten
for repair
Use larger diameter or shorter hose
Troubleshooting
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