two stage hydraulic pump adjustment brands

This 2-Stage pump fits a wide variety of log splitters and outdoor power equipment and works in both horizontal and vertical orientations. The included inlet nipple requires a 1" inner diameter suction hose.

Rated for up to 3,000 PSI at 3,600 RPM, this pump can power log splitters from 5 to 35 tons, depending on the inner diameter of the hydraulic cylinder. It features a fast cycle time by moving quickly when unloaded. It automatically shifts to low-flow/high-pressure mode at 500 PSI.

Be sure to use AW-32 10-Weight (ISO 32) or AW-46 20-Weight (ISO 46) light hydraulic fluid or Dexron III automatic transmission fluid. This pump is not designed for use with “universal” or "tractor" transmission oil, such as "303". The use of incorrect fluid may damage the pump and void the warranty.

Make sure the hydraulic fluid reservoir is not below the pump to ensure a sufficient flow of fluid to the pump. Suction-side filtration should be no finer than 150 microns. The use of a 10-25 micron filter on the suction side of the pump is too restrictive and will cause failure.

The mounting flange on this pump has a 4-bolt, 2 inches on center, mounting pattern. The bolt circle is 2.85" and the bolt hole diameter is M8 (.344").

This 2-Stage pump fits a wide variety of log splitters and outdoor power equipment and works in both horizontal and vertical orientations. The included inlet nipple requires a 1" inner diameter suction hose.

Rated for up to 3,000 PSI at 3,600 RPM, this pump can power log splitters from 5 to 35 tons, depending on the inner diameter of the hydraulic cylinder. It features a fast cycle time by moving quickly when unloaded. It automatically shifts to low-flow/high-pressure mode at 500 PSI.

Be sure to use AW-32 10-Weight (ISO 32) or AW-46 20-Weight (ISO 46) light hydraulic fluid or Dexron III automatic transmission fluid. This pump is not designed for use with “universal” or "tractor" transmission oil, such as "303". The use of incorrect fluid may damage the pump and void the warranty.

Make sure the hydraulic fluid reservoir is not below the pump to ensure a sufficient flow of fluid to the pump. Suction-side filtration should be no finer than 150 microns. The use of a 10-25 micron filter on the suction side of the pump is too restrictive and will cause failure.

We recommend using an L-style jaw coupling to connect the pump to an engine. Couplings and mounting brackets are available. You should use at least a 5hp 163cc engine to maintain 3,600 RPM under load.

All of Hytec’s electric/hydraulic pumps are two-stage, continuous pressure (demand) pumps that contain all the necessary controls and circuitry for powering any single- or double-acting, continuous pressure workholding system. They contain a pressure switch and pressure regulator, and each is infinitely adjustable throughout the operating pressure range of 1,000 to 5,000 psi. An internal safety relief valve prevents possible damage from exceeding the maximum rated pressure.

The first stage provides high flow at low pressure to rapidly extend clamps and cylinders. The second stage piston pump builds and maintains pressure in the system at a preset level.

The pumps’ electrical controls include a RUN/JOG switch. When the pump is started in the RUN mode, it automatically starts and runs any time the pressure switch indicates the need for oil. When pressure builds to the switch setting, the pump stops until the next demand for oil lowers the pressure, causing the switch to start the pump again. The pump continues to cycle in this manner without operator intervention.

In the JOG mode, useful for set up and special applications, the pump will run only when the operator activates and holds the start switch. When released, the pump will stop immediately. If the pump builds pressure to the pressure switch setting, it will also stop. The pump cannot be forced to run after the pressure switch setting has been reached in either the RUN or the JOG mode.

Pumps having thermal overload protection have an integral “electrical shut-down” circuit which prevents the pump from restarting without manual intervention after either thermal overload or electrical service interruption. Motor electrical specifications are listed for each pump. For voltages and frequencies not listed, contact Hytec for more information.

They"re called “RamRunners” and that"s just what they do…run large single- or double-acting rams for fast frame straightening, wheel alignment, etc. They deliver up to 45 cu. in./min. at max. operating pressure of 10,000 PSI. The 4044 has a 2-position/2-way valve with “advance” and “return” positions and is for use with single-acting rams. The 4046 and 4057 have a 3-position/4-way valve with advance,” “hold,” and “return” positions; for use with double-acting or multiple single-acting rams. Nos. 4044 and 4046 are equipped with a 1/2 h.p. single-phase, 60 Hz, 115 volt thermal protected electric motor and are designed to start under load. No. 4057 has a 1-1/2 h.p. electric motor. The RamRunners also feature a 6 ft. remote control cord for “on/off” control. One gallon and two quarts of oil are supplied.

No. 4044 – RamRunner two-stage hyd. pump with 2-position/2-way manual valve and a 6 ft. remote control cord. Supplied with one gallon and two quarts of oil. Wt., 58 lbs.

Hydraulic pumps (sometimes erroneously referred to as "hydrolic" pumps) are devices within hydraulic systems that transport hydraulic liquids from one point to another to initiate the creation of hydraulic power. They are an important component overall in the field of hydraulics, a specialized form of power transmission that harnesses the energy transmitted by moving liquids under pressure and converts it into mechanical energy. Other types of pumps that are used to transmit hydraulic fluids may also be called hydraulic pumps. Because of the wide variety of contexts in which hydraulic systems are employed, hydraulic pumps are very important in various industrial, commercial and consumer utilities.

The term power transmission refers to the overall process of technologically converting energy into a useful form for practical applications. Three main branches compose the field of power transmission: electrical power, mechanical power, and fluid power. Fluid power encompasses the use of moving gases and well as moving liquids for power transmission. Hydraulics, then, can be considered as a sub-branch of fluid power which focuses on liquid usage as opposed to gas usage. The other field of fluid power is known as pneumatics and revolves around storing and releasing energy with compressed gas.

As described above, the incompressible nature of fluid within hydraulic systems enables an operator to create and apply mechanical power in a very efficient manner. Practically all of the force generated within a hydraulic system is applied to its intended target.

Because of the relationship between force, area, and pressure (F = P x A), it is relatively easy to modify the force of a hydraulic system simply by modifying the size of its components.

Hydraulic systems can transmit power on par with many electrical and mechanical systems while being generally simpler at the same time. For example, it is easy to directly create linear motion with a hydraulic system. On the contrary, electrical and mechanical power systems generally require an intermediate mechanical step to produce linear motion from rotational motion.

Hydraulic power systems are generally smaller than their electrical and mechanical counterparts while generating similar amounts of power, thus providing the advantage of conserving physical space.

The basic design of hydraulic systems (a reservoir/pump connected to actuators by some sort of piping system) allows them to be used in a wide variety of physical settings. Hydraulic systems can also be used in environments that are impractical for electrical systems (e.g. underwater).

Using hydraulic systems in place of electrical power transmission increases relative safety by eliminating electrical safety hazards (e.g. explosions, electric shock).

A major, specific advantage of hydraulic pumps is the amount of power they are able to generate. In some cases, a hydraulic pump can produce ten times the amount of power produced by an electrical counterpart. Some types of hydraulic pumps (e.g. piston pumps) are more expensive than the average hydraulic component. These types of disadvantages, however, may be offset by the pump’s power and efficiency. For example, piston pumps are prized for their durability and ability to transmit very viscous fluids, despite their relatively high cost.

The essence of hydraulics lies in a fundamental physical reality: liquids are incompressible. Because of this, liquids resemble solids more than compressible gases. The incompressible nature of liquid enables it to transmit force very efficiently in terms of force and speed. This fact is summarized by a version of "Pascal’s Law" or "Pascal’s Principle", which states that virtually all of the pressure applied to any part of a (confined) fluid will be transmitted to every other part of the fluid. Using alternative terms, this scientific principle states that pressure exerted on a (confined) fluid transmits equally in every direction.

Furthermore, force transmitted within a fluid has the potential to multiply during its transmission. From a slightly more abstract point of view, the incompressible nature of liquids means that pressurized liquids must maintain a constant pressure even as they move. Pressure, from a mathematical point of view, is force acting per a specific area unit (P = F/A). A rearranged version of this equation makes it clear that force equals the product of pressure times area (F = P x A). Thus, by modifying the size or area of certain components within a hydraulic system, the force acting within a hydraulic system can also be modified accordingly (to either greater or lesser). The need for pressure to stay constant is responsible for making force and area reflect each other (in terms of either growing or shrinking). This force-area relationship can be illustrated by a hydraulic system containing a piston that is five times bigger than a second piston. if a certain force (e.g. 50 pounds) is applied to the smaller piston, that force will be multiplied by five (e.g. to 250 pounds) as it is transmitted to the larger piston within the hydraulic system.

The chemical nature of liquids as well as the physical relationship between force, area, and pressure form the foundation of hydraulics. Overall, hydraulic applications enable human operators to create and apply massive mechanical forces without exerting much physical effort at all. Water and oil are both used for power transmission within hydraulic systems. The use of oil, however, is far more common, due in part to its very incompressible nature.

It has previously been noted that "Pascal’s Law" applies to confined liquids. Thus, for liquids to act in a hydraulic fashion, it must function with some type of enclosed system. An enclosed mechanical system that uses liquid hydraulically is known as a hydraulic power pack or a hydraulic power unit. Though specific operating systems are variable, all hydraulic power packs (or units) have the same basic components. These components generally include a reservoir, a pump, a piping/tubing system, valves, and actuators (including both cylinders and motors). Similarly, despite the versatility and adaptability of these mechanisms, these components all work together within similar operating processes, which lie behind all hydraulic power packs.

Hoses or tubes are needed to transport the viscous liquids transmitted from the pump. This piping apparatus then transports the solution to the hydraulic cylinder.

Actuators are hydraulic components which perform the main conversion of hydraulic energy into mechanical energy. Actuators are mainly represented by hydraulic cylinders and hydraulic motors. The main difference between hydraulic cylinders and hydraulic motors lies in the fact that hydraulic cylinders primarily produce linear mechanical motion while hydraulic motors primarily produce rotary mechanical motion.

Hydraulic systems possess various valves to regulate the flow of liquid within a hydraulic system. Directional control valves are used to modify the size and direction of hydraulic fluid flow, while pressure relief valves preempt excessive pressure by limiting the output of the actuators and redirecting fluid back to the reservoir if necessary.

Two main categories of hydraulic pumps to be considered are piston pumps and gear pumps. Within the piston grouping are axial and radial piston pumps. Axial pumps provide linear motion, while radial pumps can operate in a rotary manner. The gear pump category is also divided into two groupings, internal gear pumps and external gear pumps.

No matter piston or gear, each type of hydraulic pump can be either a single-action or double-action pump. Single-action pumps can push, pull or lift in only one direction, while double-action pumps are multidirectional.

The transfer of energy from hydraulic to mechanical is the end goal, with the pump mechanism serving as a generator. In other cases, however, the energy is expelled by means of high pressure streams that help to push, pull and lift heavy loads.

Hydraulic piston pumps and hydraulic clutch pumps, which operate in slightly different ways, are all utilized in heavy machinery for their versatility of motion and directionality.

And hydraulic water pumps are widely used to transfer water. The design of these pumps dictates that, although a small amount of external energy is needed to initiate the action, the weight of the water and its movement can create enough pressure to operate the pump continuously thereafter. Hydraulic ram pumps require virtually no maintenance, as they have only two moving parts. Water from an elevated water source enters one of two chambers through a relatively long, thick pipe, developing inertia as it moves down to the second chamber, which starts the pump.

The initial energy within a hydraulic system is produced in many ways. The simplest form is the hydraulic hand pump which requires a person to manually pressurize the hydraulic fluid. Hydraulic hand pumps are manually operated to pressurize a hydraulic system. Hydraulic hand pumps are often used to calibrate instruments.

Energy-saving pumps that are operated by a compressed air source and require no energy to maintain system pressure. In both the single and two-stage air hydraulic pumps, air pressure is simply converted to hydraulic pressure, and they stall when enough pressure is developed.

Non-positive displacement pumps that are used in hydraulics requiring a large volume of flow. Centrifugal pumps operate at fairly low pressures and are either diffuser or volute types.

Convert hydraulic energy to mechanical power. Hydraulic pumps are specially designed mechanisms used in industrial, commercial and residential settings to create useful energy from the pressurization of various viscous fluids. Hydraulic pumps are extremely simple yet effective mechanisms for moving liquids. "Hydralic" is actually a misspelling of "hydraulic;" hydraulic pumps rely on the power provided by hydraulic cylinders to power various machines and mechanisms.

Pumps in which the clamps and cylinders are quickly extended by high flow at low pressure in the first stage of operation. In the second stage, piston pumps build pressure to a preset level and then maintain that level.

The construction, automotive manufacturing, excavation, agriculture, defense contracting and manufacturing industries are just a few examples of operations that utilize the power of hydraulics in normal, daily processes. Since the use of hydraulics is so widespread, hydraulic pumps are naturally used in a broad array of industries and machines. In all of the contexts which use hydraulic machinery, pumps perform the same basic role of transmitting hydraulic fluid from one place to another to create hydraulic pressure and energy (in conjunction with the actuators).

Various products that use hydraulics include elevators, automotive lifts, automotive brakes, airplane flaps, cranes, shock absorbers, motorboat steering systems, garage jacks, log splitters, etc. Construction sites represent the most common application of hydraulics in large hydraulic machines and various forms of "off-highway" equipment such as diggers, dumpers, excavators, etc. In other environments such as factories and offshore work areas, hydraulic systems are used to power heavy machinery, move heavy equipment, cut and bend material, etc.

While hydraulic power transmission is extremely useful in a wide variety of professional applications, it is generally unwise to depend exclusively on one form of power transmission. On the contrary, combining different forms of power transmission (hydraulic, pneumatic, electrical and mechanical) is the most efficient strategy. Thus, hydraulic systems should be carefully integrated into an overall strategy of power transmission for your specific commercial application. You should invest in finding honest and skilled hydraulic manufacturers / suppliers who can assist you in developing and implementing an overall hydraulic strategy.

When selecting a hydraulic pump, its intended use should be considered when selecting a particular type. This is important since some pumps may carry out only one task, while others allow more flexibility.

The material composition of the pump should also be considered in an application-specific context. The pistons, gears and cylinders are often made of durable materials such as aluminum, steel or stainless steel which can endure the constant wear of repetitive pumping. The materials must hold up not only to the process itself, but to the hydraulic fluids as well. Oils, esters, butanol, polyalkylene glycols and corrosion inhibitors are often included in composite fluids (though simply water is also used in some instances). These fluids vary in terms of viscosity, operating temperature and flash point.

Along with material considerations, manufacturers should compare operating specifications of hydraulic pumps to ensure that intended use does not exceed pump capabilities. Continuous operating pressure, maximum operating pressure, operating speed, horsepower, power source, maximum fluid flow and pump weight are just a few of the many variables in hydraulic pump functionality. Standard measurements such as diameter, length and rod extension should also be compared. As hydraulic pumps are used in motors, cranes, lifts and other heavy machinery, it is integral that they meet operating standards.

It is important to remember that the overall power produced by any hydraulic drive system is affected by various inefficiencies that must be taken into account to get the maximum use out of the system. For example, the presence of air bubbles within a hydraulic drive is notorious for diverting the energy flow within the system (since energy gets wasted en route to the actuators on compressing the bubbles). Using a hydraulic drive system must involve identifying these types of inefficiencies and selecting the best components to mitigate their effects. A hydraulic pump can be considered as the "generator" side of a hydraulic system which begins the hydraulic process (as opposed to the "actuator" side which completes the hydraulic process). Despite their differences, all hydraulic pumps are somehow responsible for displacing fluid volume and bringing it from the reservoir to the actuator(s) via the tubing system. Pumps are generally enabled to do this by some type of internal combustion system.

Even though hydraulic systems are simpler when compared to electrical or mechanical systems, they are still sophisticated systems that should only be handled with care. A fundamental safety precaution when interacting with hydraulic systems is to avoid physical contact if possible. Active fluid pressure within a hydraulic system can pose a hazard even if a hydraulic machine is not actively operating.

Insufficient pumps can lead to mechanical failure in the workplace, which can have serious and costly repercussions. Although pump failure has been unpredictable in the past, new diagnostic technologies continue to improve on detection methods that previously relied upon vibration signals alone. Measuring discharge pressures allows manufacturers to more accurately predict pump wear. Discharge sensors can be easily integrated into existing systems, adding to the safety and versatility of the hydraulic pump.

A container that stores fluid under pressure and is utilized as a source of energy or to absorb hydraulic shock. Accumulator types include piston, bladder and diaphragm.

A circumstance that occurs in pumps when existing space is not filled by available fluid. Cavitation will deteriorate the hydraulic oil and cause erosion of the inlet metal.

Any device used to convert potential energy into kinetic energy within a hydraulic system. Motors and manual energy are both sources of power in hydraulic power units.

A slippery and viscous liquid that is not miscible with water. Oil is often used in conjunction with hydraulic systems because it cannot be compressed.

A device used for converting hydraulic power to mechanical energy. In hydraulic pumps, the piston is responsible for pushing down and pulling up the ram.

A hydraulic mechanism that uses the kinetic energy of a flowing liquid to force a small amount of the liquid to a reservoir contained at a higher level.

A device used to regulate the amount of hydraulic or air flow. In the closed position, there is zero flow, but when the valve is fully open, flow is unrestricted.

There might be a necessity to change the hydraulic pump pressure, which is fortunately possible. The pressure imbalance can occur due to the difference in flow inside the pump. Since such a pump has several actuators, they fluctuate.

So how to adjust a hydraulic pump output pressure? So, here we have described the processes for you to adjust the pressure easily at home with simple tools.

The thing with a hydraulic pump is that we can’t adjust the pressure, but maintain the flow such that the pressure remains stable. This can be done in different ways.

Those pumps that have a pressure control adjustment can be easily fixed. Simply change the pressure on the swashplate when the pressure seems too high. For other pumps with an open system, you will get a PSV that will show the pressure that will need to be adjusted.

To adjust the pressure, we need to change the speed of flow since pumps generate the speed only. This will ensure that the pressure doesn’t increase and remains balanced.

In some cases, we can’t simply adjust the pressure. We can add a pressure relief valve for a bypass flow in the pump to pour some oil whenever the pressure becomes too high. Some pumps have valves that regulate the flow speed. So, we can adjust the valve opening to change the pressure level.

We can easily add any kind of relief valve to the pump to maintain the pressure. Even though valves don’t adjust the pressure themselves, we can add these to lower the pressure whenever it increases.

Sometimes, a valve includes a compensator valve as well to regulate the pressure. The compensator will remain in the required pressure setting. When the pressure increases, this adjustment will limit the system pressure.

It consists of both a positive and negative flow control system. The positive flow control will increase the flow, by discharging the necessary speed to increase the pressure without power wastage.

Usually, this hydraulic pressure pump has an adjustable piston to regulate the pressure itself. The valves inside the monitors create pressure to control the swashplate. When the angle increases, the speed increases, as well as the pressure.

So, this pump also has two valves for pressure adjustment. The internal mechanism regulates both pressures and flows according to the system demand. When needed, the pressure and flow are both high, and at other times come to zero, following displacement changes.

The Parker hydraulic pump also comes with two separate valves for pressure adjustment. So, we need to fix the compensator valve to change the pressure. Whenever the system alerts for higher pressure inside the system, the compensator valve will detect this. It will cause the output pressure to drop.

The pressure adjustment in this pump involves the use of a wrench to turn the screw according to the demand. When the pressure becomes high, a wrench, usually the size of 1/8 inch is used to turn the screw slowly in an anti-clockwise direction.

The user needs to hold the wrench steady so that the pressure comes to an acceptable level. If the wrench is used clockwise, the pressure will increase for adjustment. We need to be careful to avoid overdoing it for the adjustment.

It is very important to keep the pressure level balanced inside the hydraulic pump to make the fluid flow smooth. Besides, we can also reduce many damages in this way. All we have to do is monitor the pressure so that it doesn’t exceed the acceptable range.

Most hydraulic pumps are able to handle a pressure range from 500 to around 15000 psi for the received fluid. The pumps are given the fluid via a reservoir to reach the actuator to operate it. So, by checking the actuator we can understand if the pressure is in the acceptable range. The fluid flow should also be at a speed of around 600 GPM to maintain pressure.

A load-sensing compensator works to maintain the pressure of the hydraulic system. It will adjust its pressure and speed of flow according to the fluid flowing into the system. So, the flow becomes continuous with a balance in output pressure.

It will automatically drop or increase the flow by sensing the pressure level. We can also release the pressure of the compensator to fix the pump pressure.

Most pressure pumps include a relief valve or are recommended to add one. This valve is the media through which we can adjust the pressure. Usually, it reduces the pressure whenever it becomes too high to prevent any harm to the system.

This also protects other parts in the pump from excessive pressure buildup. Since the pressure remains at a set level as accepted, the system works perfectly without fail. If the pressure goes up the given level, the relief valve will work to limit the fluid flow to the tank.

As mentioned, a pressure compensator helps further to decrease the pump flow whenever the pressure becomes high. This helps the user to keep the system free from damage if they can’t adjust the pressure manually on time. It will automatically reduce the pressure when it exceeds the set level. The pump flow is at first maintained to adjust the pressure as needed.

The pressure level, either a high or low range is simple to adjust by changing the setting of the pressure gauge. Use a wrench to turn the adjustment screw in a certain direction to change the pressure. To make it high, the adjustment screw is moved by a clockwise rotation.

The pressure output of the hydraulic is simple to adjust either using the internal mechanism or using a spare part. However, it is usually the flow inside that needs to change to maintain pressure. Simply fix the valve in the right direction to adjust the pressure.

The hydraulic pump needs a valve system to regulate the pressure. We can use a tool to fix the jammed nut to release pressure. The adjustment knob is also turned in the right direction to make the pressure high or low according to the system’s demand.

Again this involves the use of an adjustment knob. In most cases, this is included in the hydraulic system. By rotating the knob in the clockwise direction, we can raise the pressure in the power pack easily.

Any valve adjustment usually depends on its type. The one on the hydraulic system is commonly a relief valve for regulating pressure. The valve is turned in the clockwise direction to get the desired pressure reading on the gauge. This is also the starting pressure of the valve.

You can use a tool to loosen the load sensing pump by rotating it in the clockwise direction. This will prevent excess pressure to build up in the pump, which will also stop high-pressure build-up in the whole system.

Firstly, fix the hydraulic gauge on the back using a screwdriver. Then you can change the pressure switch using a wrench to make it looser. As the lock-nut is no longer jammed, the pressure will drop.

When the hydraulic system is operated, it is inevitable that the pressure level will change according to the fluid displacement. As the fluid enters the system and flows, the pressure can either become high or low.

Every hydraulic pump will have the desired pressure range, and when it is below and above the range, problems arise in the whole system, which can even become dangerous. This guide on how to adjust a hydraulic pump output pressure helps you to adjust the pressure switch.

http://www.energymfg.com/pdf/16445x.pdfGood catch, I should have seen that. Now the interesting part is that the relief is preset 2000psi from factory and a max range of 2500psi. His engine should pull that without any serious bogging. Rereading the first post, he says it boggs out and stalls. I am now wondering if its the engine that is stalling, ( which is what I thought he was saying),or the cylinder that is stalling. I think that issue needs to be clarified before going any further. If the cylinder is what is stalling, and the engine continues to run, it could just be a matter of the relief being set to low, or to small a cylinder for the wood being split. If it is indeed not shifting into lowflow/high pressure, then he might need to adjust the pump to the the 650psi high flow/ low pressure. Remove the cap on the inlet side of the pump. Under the cap is a slotted screw. Turn clockwise to increase pressure. Turn the screw all the way clockwise to the stop and see if the engine can handle it. If not then back it out a little and try again. Run the engine full throttle and plan to play with the setting until you find the limit for your engine. You will find that the higher you can run the pressure on high flow side, the less the pump will kick down into low flow/high pressure and the faster your splitter will work. If you engine is actually already what is bogging, you may have to turn the screw counter clockwise to lower the unloader pressure.. It is best to use a pressure gauge, but you can do this by ear. If its killing the engine, just turn the screw out until it no longer kills the engine. You should adjust the relief setting on the control valvle first before trying to adjust the unloader valve on the pump. The load is what will cause the pressure to build, you can simulate a full load by fully extending or retracting the cyl, and the relief valve on the valve will activate. If it will not get to 2500 psi, then the valve pressure relief (on control valve) is not set, or you don"t have a load equivalent to 2500 psi. With a gauge installed, pressure will be at a minimum until you activate the lever on the control valve, Once lever is activated, pressure should climb on the gauge until the cyl is fully extended or retracted, at which point the pressure will climb rapidly to the relief setting. Watch the gauge, it should jump from the settings on the pump unloader valve (650psi), to the setting on the relief (2500psi). You may need to split a round or two to actually see the pressure spike as the spike can be pretty fast

I will just add, that I have never had to adjust the relief on the control valve or unloader relief on a pump that was new out of the box. Usually if the reliefs need adjusting, its because someone has already been messing with them. Usually the factory guys have it pretty close, not saying mess ups dont happen, just that it is unusual when it does. I also usually use large bore cyls and bigger hp engines than the minimums required. If you have the hp to pull the pumps and cyls that create more than enough force, the factory relief setting will usually take care of themselfs.

.On that two stage pump it could have sucked some dirt,dust whatever into the pump and stuck the pump bypass valve which switches it to high pressure low volume .That valve should be set at around 900-1000 PSI . The relief valve in the main control valve is where the max system pressure is set on most splitters

If you can figure out what brand of pump it is more than likely an internet search will provide some troubleshooting information .You might try "Surplus Center" hydraulics which has some information available .

· 16GPM Powerful Pump: This hydraulic pump comes with a 25 GPM auto control detent valve. It features a 3600 RPM max rotating speed, 2250PSI valve setting along with a 16GPM high flow rate. It will bring powerful performance to your log splitter. Get ready to start cutting logs in half, in half the time.

· 1" Inlet & 1/2" NPT Outlet: Our log splitter pump is equipped with a standard 1/2" NPT outlet port ( for Minimum 8 HP engine) and 1" barb on the inlet port. It also has a 1/2" diameter shaft with a 3/8" key, allowing it to rotate clockwise. Quality you can trust, for unmatched results you can see.

· Sturdy ＆ Durable: The high-strength extrusion aluminum casing enables the pump to resist impact, rust, and high pressure. This sturdy structure can prevent leaks and ensure a prolonged service life.

· Simple Installation: This pump stands out with a 4-hole bolt-on design, and it allows for a direct and quick installation. Install the pump effortlessly, making your log splitting more effective and robust.

· Doesn"t Just Split Logs: The 2-stage hydraulic pump is excellent for log splitters, press, machine tools, and power units for snowplows. It has outstanding compatibility with many OEMs like Speeco, Huskee, Champion, and many more.