Troubleshooting
Symptom
Possible Cause
Corrective Action
Oil leak between crankcase
and pump section
Worn oil seals around plunger Replace crankcase plunger oil seals
Frequent or premature
failure of the packing
1. Cracked, damaged, or worn
plunger
1. Replace plunger
2. Overpressure to inlet
manifold
2. Reduce inlet pressure
3. Material in the fluid being
pumped
3. Install filter to pump inlet
4. Excessive pressure and/or
temperature of fluid being
pumped
4. Check pressure and water inlet tempera-
ture. Be sure they are within specified ranges
5. Running pump dry
5. Do not run pump without water
Pump runs but produces
no flow
Pump is not primed
Flood suction then restart the engine
Pump fails to prime
Air is trapped inside pump
Disconnect discharge hose from pump. Flood
suction hose and run the pump until all air
has been evacuated
Pump loses prime, chatter-
ing noise, and/or pressure
fluctuates
1. Air leak in suction hose or
inlet
1. Remove suction line and inspect it for
a loose liner or debris lodged in the hose.
Avoid all unnecessary bends and do not kink
2. Clogged suction strainer
2. Clean strainer
Low pressure at nozzle
1. Unloader valve is
by-passing
1. Make sure unloader is adjusted properly
and by-pass seat is not leaking
2. Incorrect or worn nozzle
2. Make sure nozzle is matched to the flow
and pressure of the pump. If the nozzle is
worn the replace it with a new one.
3. Worn packing or valves
3. Replace packing or valves
Pressure gauge fluctuates
1. Valves worn or blocked by
debris
1. Clean or replace valves
2. Packing worn
2. Replace packing
Low pressure
1. Worn nozzle
1. Replace with new nozzle of proper size
2. Air leak in inlet connection
2. Disassemble, reseal, and reassemble
3. Relief valve stuck, partialy
plugged or improperly adjust-
ed valve seat, valve seat worn
3. Clean and adjust relief valve and check for
worn or dirty vavle seats
4. Worn packing. Abrasive in
pump cavitation. Inadequate
water.
4. Install proper filter at manifold water inlet
5. Worn inlet, discharge valve
blocked or dirty
5. Replace inlert and discharge valve
Pump runs extremely rough,
pressure very low
1. Inlet restrictions and or air
leak
1. Clean out foreign material
2. Stuck inlet or discharge
valve
2. Replace worn valve