Troubleshooting - Graco GH 300 Repair Manual

Troubleshooting

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
The sprayer overheats
Spitting from gun
Excessive hydraulic pump noise
Electric motor does not operate
*Check hydraulic fluid level often. Do not allow it to become too low. Use only Graco approved hydraulic fluid.
8
Troubleshooting
CAUSE
Hydraulic pressure is too high
Switch OFF, low oil, no gasoline
Faulty engine
Elevation
Hydraulic 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 or broken or off
Hydraulic pump worn or damaged
Dried paint seized paint pump rod
Hydraulic motor not shifting
Piston ball check not seating properly
Piston packings worn or damaged
Piston packings worn or damaged
Intake valve ball check not seating
properly
Suction tube air leak
Loosen 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
Large pressure drop in fluid hose
Paint buildup on hydraulic components
Air in fluid pump or hose
Loose intake suction
Fluid supply is low or empty
Low hydraulic fluid level
Power switch is not ON
Tripped circuit breaker
SOLUTION
Turn hydraulic pressure knob counter clock-
wise to lowest setting.
Consult engine manual, supplied.
Consult engine manual, supplied.
Refer to Engine Repair Kit.
4.0 hp - 288678 / 5.5 hp - 248943 /
6/5 hp - 248944 / 9.0 hp - 248945
Set hydraulic pump valve ON.
Increase pressure.
Clean the filter.
Remove tip and/or filter and clean.
Shut off sprayer. Add fluid*.
Replace, page 12.
Bring sprayer to Graco distributor for repair.
Service pump. See manual 311845.
Set pump valve OFF. Turn pressure down.
Turn engine OFF. Pry rod up or down until
hydraulic motor shifts .
Service piston ball check. See manual
311845.
Replace packings. See manual 311845.
Tighten packing nut or replace packings.
See manual 311845.
Service intake valve ball check. See man-
ual 311845.
Tighten wet-cup enough to stop leakage.
Replace packings. See manual 311845.
Replace these parts.
Increase pressure.
Clean filter.
Tighten.
Bring sprayer to Graco distributor for repair.
Use larger diameter or shorter hose.
Clean.
Check for loose connections on siphon
assembly, tighten, then reprime pump.
Tighten.
Refill supply container.
Turn sprayer OFF. Add fluid*.
Turn power switch to ON.
Check circuit breaker at power source.
Reset motor switch.
311797F