Kawasaki K3V and K3VL Regulator Adjustment and Excavator Main Pump Troubleshooting

On a Kawasaki K3VL, the regulator has separate screws for cut-off pressure, load sense differential, maximum flow and (if fitted) the torque limiter's outer and inner springs; turning the pressure screws clockwise raises the setting, and Kawasaki publishes how much each turn moves it. On a K3V or K5V excavator main pump, Kawasaki's catalog gives no adjustment values at all, the settings belong to the machine maker, and a weak or slow excavator is more often a relief valve, pilot signal, engine or control valve problem than a regulator that has drifted.

So the rule in our shop is simple: prove it is the pump before anyone touches a screw. Most regulators we see that were "adjusted" in the field were fine until someone went looking for lost power in the wrong place.

Which Kawasaki regulator do I have?

Read the nameplate first (our Kawasaki identification guide shows where it is). The regulator is coded in the model number, and the two families code it differently.

K3V and K5V (excavator tandem pumps)

Kawasaki's example ordering code is K3V 280 DT H 100 R 2N 01: series, displacement in cc, DT for a tandem (DP parallel, S single), an option letter (H with a centrifugal pump, P with a PTO), a design code, R or L for clockwise or counterclockwise viewed from the shaft end, the regulator code (2N here), and the regulator design code. The regulator code is a horsepower control digit plus a flow control letter.

Code	Control	What it does, per Kawasaki
1	Constant horsepower	As delivery pressure rises the swashplate angle drops, holding input torque constant
2	Total horsepower	Same, plus each pump's power is cut back as the companion pump's pressure rises
4, 5, 6	High pressure cut-off	Above the set pressure, flow is cut back (alone, with horsepower control, or with total horsepower control)
9	Variable horsepower	The horsepower setting is shifted by a pilot pressure or an electric current
M	Manual flow control	Flow follows a lever stroke
P	Positive flow control	Flow rises as pilot pressure rises
N	Negative flow control	Flow falls as pilot pressure rises
C	Two-stage max flow	A second maximum flow selected by external pilot pressure (negative control only)
L	Load sensing	Holds pump pressure a set margin above load pressure
E	Electric flow control	Flow follows an electric current

Kawasaki's listed combinations include 10, 20, 60 (total horsepower plus cut-off), 2P, 2N, 9L, 2C and 9N. 2N and 9N are negative flow control plus total horsepower control, the 9N adding variable horsepower. The code on your plate is the one that counts.

K3VL (industrial, marine and mobile single pumps)

K3VL regulators are P0 (pressure cut-off), L0 or L1 (load sense with cut-off; L1 has the R4 bleed orifice plugged, so the circuit needs a bleed elsewhere), PM/PN and LM/LN (with an integral unloading valve), and PV/PV2 and LV/LV2 (with an integral proportional relief). A suffix such as /1-H1 adds a torque limiter, where S, L, M and H are the spring range and the number is the setting. /1-E0 and /1-Q0 add electric or pilot displacement control.

Which adjustment screw does what on a K3VL regulator?

All figures below are from Kawasaki Precision Machinery's K3VL technical brochure (P-969-0274D, 2017), which is the factory regulator adjustment PDF for the K3VL; the adjustment tables are on printed page 64. Turning the cut-off and differential screws clockwise increases the setting.

Adjustment	Factory standard and range	Change per screw turn	Tools and lock-nut torque
Cut-off pressure (P0, L0, L1)	Standard 4,600 psi (320 bar); range 300 to 4,600 psi (21 to 320 bar)	K3VL28: 1,160 psi (80 bar). K3VL45/60/80: 580 psi (40 bar). K3VL112/140/200: 1,330 psi (92 bar)	4 mm internal hex; 13 mm lock-nut, 12 lbf-ft (16 Nm)
Differential pressure (load sense margin)	Standard 218 psi (15 bar); range 145 to 300 psi (10 to 21 bar) per the L0/L1 description	K3VL28 and 45/60/80: 188 psi (13 bar). K3VL112/140/200: 80 psi (5.5 bar)	4 mm internal hex; 13 mm lock-nut, 12 lbf-ft (16 Nm)
Torque limiter, outer spring	Factory preset to the horsepower code on the nameplate	Not published	27 mm external hex; 41 mm lock-nut, 75 lbf-ft (102 Nm)
Torque limiter, inner spring	Factory preset	Not published	4 mm internal hex; 13 mm lock-nut, 12 lbf-ft (16 Nm)

Note the K3VL60 is rated 3,625 psi (250 bar) continuous, not 4,600 psi, so keep its cut-off at or below that rating rather than at the 4,600 psi standard of the other frames.

Maximum flow screw

Frame	Hex	Displacement change per turn	Adjustable range	Lock-nut, torque
K3VL45	8 mm	0.30 in³ (4.9 cc)	0.98 to 2.75 in³ (16 to 45 cc)	24 mm, 94 lbf-ft (128 Nm)
K3VL60	8 mm	0.37 in³ (6.1 cc)	1.65 to 3.70 in³ (24 to 60 cc)	24 mm, 94 lbf-ft (128 Nm)
K3VL80	8 mm	0.36 in³ (6.0 cc)	2.15 to 4.88 in³ (35 to 80 cc)	24 mm, 94 lbf-ft (128 Nm)
K3VL112	10 mm	0.70 in³ (11.5 cc)	3.42 to 6.83 in³ (56 to 112 cc)	30 mm, 173 lbf-ft (235 Nm)
K3VL140	10 mm	0.73 in³ (12.0 cc)	4.27 to 8.54 in³ (70 to 140 cc)	30 mm, 173 lbf-ft (235 Nm)
K3VL200	10 mm	0.93 in³ (15.3 cc)	6.1 to 12.2 in³ (100 to 200 cc)	30 mm, 173 lbf-ft (235 Nm)

Kawasaki also lists the exposed screw length for each frame. Measure it before you touch the screw and write it down; it is the only record you will have of where the pump was set.

How the torque limiter adjusts

The torque limiter has two springs. The outer spring adjustment moves the top half of the pressure-flow curve and the inner spring adjustment moves the bottom half. Clockwise increases. Changing the outer adjustment shifts both springs, but the inner adjustment does not affect the outer, so Kawasaki says to set the outer first and then the inner. To check what a setting should be, Kawasaki's formula is torque (lbf-ft) = horsepower x 5,252 / rpm, and the brochure's setting table maps each code to a horsepower at 1,150 and 1,750 rpm input.

Remote control: on P0 types a relief valve on the Pc port sets the pump remotely, and Kawasaki puts the pilot flow from that port at about 0.4 gpm (1.5 L/min). If the remote relief or its line is leaking, the pump will cut off low no matter where the screw is.

How do I adjust a Kawasaki hydraulic pump, and in what order?

Kawasaki gives the order only for the torque limiter (outer, then inner). The rest is how we do it in the shop, and the logic applies to any pressure-compensated piston pump:

1. Find out why you are adjusting. If the pump has been running fine for years, a lost setting is the least likely cause. Do the tests in the next section first.
2. Install gauges at the pump delivery port, the load sense or Pc port, and the case drain. Bring the oil to normal working temperature and take a baseline reading with nothing changed.
3. Record where everything is. Mark each screw against its body and measure exposed lengths before loosening a lock-nut.
4. Check the system relief. It should sit above the pump cut-off so the regulator does the work and the relief only catches spikes. A relief set below the cut-off dumps oil over the valve as heat.
5. Set cut-off pressure with the outlet blocked or the function stalled, turning in small steps and using the per-turn figure above to predict each move.
6. Set the differential (standby) pressure on load sense types with all functions in neutral.
7. Set the torque limiter, outer then inner, while watching engine or motor speed under load.
8. Set max flow last, if it needs changing at all, and hold each screw while you torque its lock-nut to the figure in the table.

Why is my excavator main pump weak or slow?

On a K3V or K5V excavator pump the regulator is answering signals from the rest of the machine: pilot pressure from the control valve's flow control circuit, the companion pump's pressure for total horsepower control, and on variable horsepower types a pilot pressure or electric current that the machine sets. When those signals are wrong, a perfectly good pump will look weak. Kawasaki's K3V/K5V catalog publishes no adjustment rates or factory settings for these regulators, because the machine maker sets them for its engine and valve. Use the shop manual for your machine model, and be careful with a manual found online for a different machine: the same pump size carries different regulator codes on different excavators.

Symptom	Check first	Points to the pump when
Everything slow, engine not working hard	Pilot supply pressure, the flow control (negative or positive) signal at the regulator, engine speed setting	Signal pressures are correct but flow at full stroke is low, or case drain flow is high
Weak: stalls under load, low pressure on every function	Main relief on the control valve, pressure cut-off setting, port reliefs	Relief is set right and does not open, but the pump still will not make pressure
Engine bogs or stalls under load	Engine power and fuel, horsepower or torque setting, variable horsepower signal (solenoid current or pilot)	Rarely the pump hardware; usually the horsepower setting is too high for the engine or the engine has lost power
One pump of the tandem weak (one side of the machine, or travel tracks off)	That pump's flow control signal line, its half of the control valve, the companion pump's pressure (total horsepower control cuts one pump when the other is loaded)	Case drain flow or flow test on that pump is out of line with the other at the same conditions
Overheating	Relief valves bypassing, cut-off set above the relief, cooler, oil level	Case drain flow is high or case pressure is over the limit
Noisy, whining, rattling	Suction strainer, air in the oil, low oil, coupling alignment	Noise stays with the pump after the suction side is proven, or metal shows in the drain filter

One more trap on tandem pumps: with total horsepower control, each pump gives up power as its companion pump's pressure rises. A side that "goes weak" whenever the other side is working hard may be the control doing exactly what it was built to do.

How do I troubleshoot a Kawasaki pump: is it the pump, the control valve or the engine?

• Pressure and relief. Stall one function at a time and read delivery pressure at the pump. If every function stops at the same low pressure, look at the main relief before the pump. If the relief is correct and the pump cannot reach it, the pump or its regulator is in the frame.
• Signals. Read the flow control pilot pressure at the regulator in neutral and with a lever fully stroked. On a negative control pump, a signal that stays high keeps the pump at low flow no matter what the operator does.
• Case drain. Measure case drain flow and pressure on each pump. Kawasaki limits K3V/K5V case pressure to 0.1 MPa (about 15 psi) normally and 0.4 MPa (about 58 psi) peak. A worn rotating group shows up as high drain flow before anything else; our case drain flow test guide covers the method.
• Engine. Watch engine speed as you load the system. A big droop with normal pressures means the pump is asking for more power than the engine has, which is a setting or engine problem, not a pump wear problem.

What causes Kawasaki pump regulators to fail?

Dirt, mostly. A regulator is a set of close-fit spools, and a sticking spool gives you a pump that hunts, will not destroke, or will not come up to flow. Kawasaki asks for oil kept to at least NAS 1638 class 9, a 10 micron return filter and an 80 to 150 mesh suction strainer, with oil viscosity between 10 and 1,000 cSt and oil temperature between -20 and +95 °C. Installation matters too: fill the case with system oil through the drain before starting, use the upper drain port with a line at least as large as the port, and run the drain loop above the top of the case. Our start-up procedure and cleanliness guide go through both.

If the regulator on a K3VL112 or K3VL140 is leaking at its seals, that is a seal kit job: we stock the genuine Kawasaki K3VL112/140 regulator seal kit, the OEM kit for that regulator. If the leak is from the pump itself, the pump seal kit for those frames is P29LH100S0Y. The full K3VL regulator parts (cut-off and differential set screws, torque limiter springs and adjustment plugs) are in our K3VL112 and K3VL80 parts catalogs.

Frequently asked questions

Related reading

• Kawasaki hydraulic pump parts
• Kawasaki piston pumps and K3VL parts catalogs
• Kawasaki seal kits
• How to identify a Kawasaki hydraulic pump
• Hydraulic pump case drain flow test
• Hydraulic pump start-up procedure after a rebuild
• Troubleshooting and setting relief valves
• Why is my hydraulic pump overheating?
• Hydraulic pump not building pressure