Graco FinishPro 311911C Repair Manual page 11

Problem
Motor runs and pump strokes
Motor runs but pump does not
stroke
Motor is hot and runs
intermittently
Low air output at gun
311911C
What To Check
(If check is OK, go to next check)
1. Prime Valve Open.
2. Paint supply.
3. Intake strainer clogged.
4. Suction hose leaking air.
5. Intake valve ball and piston ball are
seating properly.
6. Leaking around throat packing nut
which may indicate worn or damaged
packings.
7. Pump rod damaged.
1. Displacement pump pin damaged or
missing.
2. Connecting rod assembly for dam-
age.
3. Gears or drive housing.
1. Be sure ambient temperature where
sprayer is located is not more than
115°F (46°C) and sprayer is not
located in direct sun.
2. Motor has burned windings indicated
by removing positive (red) brush and
seeing burned adjacent commutator
bars.
3. Tightness of pump packing nut.
Overtightening tightens packings on
rod, restricts pump action and dam-
ages packings.
1. Air valve at gun may be closed.
2. Sprayer air regulator may be closed
(FinishPro 395)
3. Air connections may be loose.
What To Do
(When check is not OK, refer to this column)
Close prime valve.
Refill and reprime pump.
Remove and clean, then reinstall.
Tighten nut. Check o-rings on swivel.
See Pump Manual 309250. Strain paint before using
to remove particles that could clog pump.
See Pump Manual 309250.
See Pump Manual 309250.
Replace pump pin if missing. Be sure retaining
spring is fully in groove all around connecting rod.
See page 13, Displacement Pump Replacement.
Replace connecting rod assembly. See page 13,
Displacement Pump Replacement.
Inspect drive housing assembly and gears for
damage and replace if necessary. See page 15,
Drive Housing Replacement.
Move sprayer to shaded, cooler area if possible.
Replace motor. See page 34, Motor Replacement.
Loosen packing nut. Check for leaking around throat.
Replace pump packings if necessary. See pump
manual 309250.
Turn air valve counter-clockwise to open.
Pull to unlock and turn air regulator clockwise to
open.
Check all connections for leaking air.
Troubleshooting
11