
308620
15
PROBLEM
CAUSE
SOLUTION
The pump output is low on
the upstroke
The inlet screen (102) is clogged.
Clean the screen.
the upstroke.
A piston ball (121) is not seating.
Service the piston ball–check. See page 31.
The piston packings are worn or damaged.
Replace the packings. See page 31.
A o-ring (119) in the displacement pump is
worn or damaged.
Replace the o-ring. See page 31.
The output of the pump is
low on the downstroke or on
The inlet screen (39) is clogged.
Clean the screen.
low on the downstroke or on
both of the strokes.
The piston packings are worn or damaged.
Replace the packings. See page 31.
An intake valve ball is not seating
properly.
Clean the intake valve. See page 31.
The engine speed is too low.
Increase the throttle setting. See Step 11, page
10.
The clutch is worn or damaged.
Replace the clutch. See page 25.
The paint leaks into the wet-
cup.
The wetcup is loose.
Tighten the wetcup just enough to stop leak-
age.
The throat packings is worn or damaged.
Replace the packings. See page 31.
A displacement rod is worn or damaged.
Replace the rod. See page 31.
The fluid delivery is low.
The inlet screen (39) is clogged.
Clean the screen.
The pressure setting is too low.
Increase the pressure. See Step 11, page 10.
The engine speed is too low.
Increase the throttle setting. See Step 11, page
10.
The fluid filter (21), the tip filter or the tip is
clogged or dirty.
Clean the filter. See page 13. Or, see the gun
instruction manual.
There is a large pressure drop in the hose.
Use a larger diameter hose.
Fluid is spitting from the gun.
There is air in the pump or the hose.
Check and tighten all the fluid connections.
Reprime the pump. See page 10.
The tip is partially clogged.
Clear the tip. See the gun instruction manual.
The fluid supply is low or empty.
Refill the fluid supply. Prime the pump. See
page 9. Check the fluid supply often to pre-
vent running the pump dry.
The pump is difficult to prime.
There is air in the pump or the hose.
Check and tighten all the fluid connections.
Reduce the engine speed and cycle the pump
as slowly as possible during priming.
The intake valve is leaking.
Clean the intake valve. Be sure ball seat is not
nicked or worn and that the ball seats well.
Reassemble the valve.
The pump packings are worn.
Replace the pump packings. See page 31.
The paint is too thick.
Thin the paint according to the supplier’s
recommendations.
The engine speed is too high.
Decrease the throttle setting before priming the
pump. See Step 7, page 10.