User's Manual

Troubleshooting
311021U 9
Displacement pump operates but output
is low on downstroke and/or on both
strokes.
Strainer (34a) is clogged Clean strainer.
O-ring in pump is worn or damaged. Replace o-ring. Manual 309277.
Intake valve ball is packed with material
or is not seating properly.
Clean intake valve. Manual 309277.
Engine speed is too low. Increase throttle setting. Manual 311018.
Suction tube air leak. Tighten suction tube.
Pressure setting is too low. Increase pressure. Manual 311018.
Fluid filter (11), tip filter or tip is clogged
or dirty.
Clean filter. Manual 311018 or 311254.
Large pressure drop in hose with heavy
materials.
Use larger diameter hose and/or reduce
overall length of hose. Use of more than 100
ft of 1/4 in. hose significantly reduces
performance of sprayer. Use 3/8 in. hose for
optimum performance (50 ft minimum).
Pump is difficult to prime Air in pump or hose Check and tighten all fluid connections.
Reduce engine speed and cycle pump as
slowly as possible during priming.
Intake valve is leaking. Clean intake valve. Be sure ball seat is not
nicked or worn and that ball seats well.
Reassemble valve.
Pump packings are worn Replace pump packings. Manual 309277
Paint is too thick Thin the paint according to the supplier’s
recommendations.
Engine speed is too high Decrease throttle setting before priming
pump. Manual 311018
High engine speed at no load Mis-adjusted throttle setting Reset throttle to 3700 - 3800 engine rpm at
no load
Worn engine governor Replace or service engine governor
Low stall or run pressure shown on
display
New pump or new packings Pump break-in period takes up to 100 gallons
of material
Faulty transducer Replace transducer
Excessive paint leakage into throat
packing nut
Throat packing nut is loose Remove throat packing nut spacer. Tighten
throat packing nut just enough to stop
leakage.
Throat packings are worn or damaged Replace packings. Manual 309277
Displacement rod is worn or damaged Replace rod. Manual 309277
Fluid is spitting from gun Air in pump or hose Check and tighten all fluid connections.
Reprime pump. Manual 311018
Tip is partially clogged Clear tip. Manual 311254
Fluid supply is low or empty Refill fluid supply. Prime pump. Manual
311018. Check fluid supply often to prevent
running pump dry.
Excessive leakage around hydraulic
motor piston rod wiper
Piston rod seal worn or damaged Replace these parts
Problem Cause Solution