Graco LineLazer II 3900 - Troubleshooting; Parts

3088746
Troubleshooting
WARNING
INJECTION HAZARD
To reduce risk of serious injury, including fluid injection or splashing in eyes or on skin, or injury from
moving parts, always follow Pressure Relief Procedure Warning, page 5, before checking, adjust-
ing, cleaning or shutting down sprayer. Disconnect spark plug!
Check everything in chart before disassembling sprayer.
PROBLEM CAUSE SOLUTION
Engine won’t start
Engine switch is OFF Turn engine switch ON
g
Engine is out of gas Refill gas tank. Honda Engines Owner’s Manual.
Engine oil level is low Try to start engine. Replenish oil, if necessary.
Honda Engines Owner’s Manual.
Spark plug cable is disconnected or damaged Connect spark plug cable or replace spark
plug
Cold engine Use choke
Fuel shutoff lever is OFF Move lever to ON position
Oil is seeping into combustion chamber Remove spark plug. Pull starter rope 3 or 4
times. Clean or replace spark plug. Try to start
engine. Keep sprayer upright to avoid oil seep-
age.
Engine operates, but dis-
placement pump does not
Pressure control switch is OFF. Turn pressure control switch ON.
gp
placement pump does not
operate.
Pressure setting is too low. Turn pressure adjusting knob clockwise to
increase pressure.
Fluid filter (318) is dirty. Clean filter. See page 27.
Tip or tip filter is clogged. Clean tip or tip filter. See gun instruction
manual.
Displacement pump piston rod is stuck due to
dried paint.
Repair pump. See manual 308798.
Connecting rod is worn or damaged. Replace connecting rod. See page 8.
Drive housing is worn or damaged. Replace drive housing. See page 9.
Electrical power is not energizing field. Check wiring connections. See page 12.
Reference control board diagnostics. Page 15.
With pressure control switch ON and pressure
turned to MAXIMUM, use a test light to check
for power between clutch terminals on control
board.
Remove black clutch wires from control board
and measure resistance across wires. At 70_
F, the resistance must be between 1.2  0.2Ω
(LL 3900); 1.7  0.2Ω (LL 5900); if not, replace
pinion housing.
Have pressure control checked by authorized
Graco dealer.
Clutch is worn, damaged, or incorrectly
positioned.
Replace clutch. See page 10.
Pinion assembly is worn or damaged. Repair or replace pinion assembly, see pg 10.