Select a category from the drop-down menu below to find answers to frequently asked questions you may have about pump identification, oil and oil seals, chemical injector issues, removing your pump from the engine, and repair assistance for seals and valves. If you cannot find what you are looking for, contact our technical support team at email@example.com.
Search by selecting a category
Why isn't the chemical injector drawing any chemical?
A chemical injector uses a small spring and ball under the hose barb as a check valve to control the chemical in and water from coming out. The check valve closes when your pump operates at high pressure, preventing water from flowing out of the chemical injector hose barb. A venturi effect (vacuum) opens the check valves when your pump operates at low pressure, drawing in the chemical. Some things that can reduce or prevent the chemical draw are:
- Having too large of a nozzle resulting in low pressure
- Having too long of a discharge hose (usually over 100 ft) creates too much back pressure
- Injector check valve stuck - be sure to clean with fresh water before storing
How do I remove the pump from my engine/motor?
Pumps mounted to engines/motors for an extended period of time can be difficult to remove. For step by step instructions on removal, review the literature link below.
Why does my engine stall when I release the trigger of the spray gun?
When the trigger is released on the gun, a check valve inside of the unloader discharge port closes and traps pressure in the hose. The unloader switches to the unloaded position and runs at low pressure until the trigger is squeezed again. .
If a pump has good pressure when the trigger is squeezed, but the engine starts to bog down, or stall when the trigger is released, inspect the check valve inside of the unloader discharge port. If the check valve is stuck, or worn, it may not seat properly and the unloader will not shift in to the unloaded position. An inexpensive check valve repair kit is usually available for the unloader. Consult the unloader, or pump data sheet (integral unloader) for repair kit information.
What type of oil does my Cat Pump require?
Cat Pumps recommends the use of its specially formulated High-Pressure Pump Oil. Cat Pumps custom-blended, High-Pressure Pump Oil is exclusively designed, tested, and proven to maximize the life of Cat Pump products. This special formulated, premium-grade, petroleum-based, ISO 68 hydraulic oil contains an advanced additive package to protect against wear, oxidation, rust, and corrosion.
- Anti-wear additives protect metal to metal drive surfaces, extending drive life
- High oxidative and chemical stability resists deposit formations and provides consistent fluid performance
- Premium anti-corrosion additives offer protection in the most demanding operating environments
Cat Pumps Genuine Crankcase Oil Part Numbers:
- 6100 Case of (12), 21 oz. bottles
- 6105 Case of (2), 2.5 gal. bottles
- 6107 (1) 21 oz. bottle
- 6109 (1) 30 gal. drum
Previously, select recommended alternative oils were acceptable. Some oil manufacturers changed their oil formulas, leading to pump problems. For this reason, Cat Pumps does not recommend the use of any alternative oils.
How much oil does my pump require?
Each pump has a sight glass; the oil level should be in the middle of the sight glass when the pump is not running. You can also reference your pumps datasheet which lists the specific amount each pump requires.
Can I use synthetic oil in my pump?
Although some synthetic oils may be acceptable, Cat Pumps does not recommend the use of them. We only recommend the use of Cat Pumps brand oil in any Cat Pump. Our special formulated premium grade, petroleum-based, ISO 68 hydraulic oil contains an advanced additive package to protect against wear, oxidation, rust and corrosion.
Which way does the pump crankshaft rotate?
Forward rotation (towards the manifold) is recommended to allow optimum lubrication of the crosshead area, ensuring exceptional drive end life. If your installation does not allow for forward rotation, reverse rotation is acceptable if the crankcase oil above the red dot in the oil gauge. This assures adequate lubrication.
Does a seal kit contain the crankcase oil seals?
No, crankcase oil seals typically last the life of the pump and are not considered a wear item such as the water seals in the fluid end of the pump.
How do I remove the oil seal?
Although the oil seals can be removed through the front of the crankcase, Cat Pumps recommends that the drive end be taken apart and the plunger rods be removed so they are not scored during the process.
Is there a special tool to remove the oil seal?
No special tools are needed. Standard metric tools are required.
How do I identify the components of the pump?
How do I identify my pump model number?
Removal of the pump manifold and measurement of plungers, or cylinders (piston pumps) may be required for complete identification. A stamp number on the end of the crankshaft will be required too. For detailed information on how to identify your pump when the model label is missing, refer to the Pump Identification Reference Bulletin at the link below.
The pump model can sometimes be identified just by sight by one of our Technical Support specialists. Emailing us some pictures of the pump may help point you in the right direction. Contact firstname.lastname@example.org.
Can I return my pressure washer directly to you?
No, repairs would need to be sent to an authorized service center or where you purchased the equipment. A warranty claim would need a return authorization through a service center or authorized distributor.
My pressure washer has no pressure anymore, what is the problem?
The pressure washer pump does not draw any chemical, what is the problem?
A chemical injector uses a small spring and ball under the hose barb as a check valve to allow the chemical to pass to the system when there is sufficient pressure drop across the injector assembly. This happens when the discharge spray is reduced, otherwise injection does not take place. Pressure can be lowered by using an oversize nozzle or by opening a variable pressure wand.
Conditions that prevent the chemical draw include:
- Incorrect nozzle size to create low pressure
- Too long of discharge hose (usually 100 ft or more), creating too much back pressure
- Injector check valve stuck, likely due to debris or poor cleaning
There is water leakage between the brass part and blue crankcase, what is the problem?
The typical cause of a pump leaking water between the manifold and the body of the pump is water making its way past the low pressure seals. This is usually caused by the low pressure seals being worn. Other reasons could be the damaged seals or a cracked plunger. Low pressure seals and plungers should be inspected and replaced if damaged.
Where does the small gasket/O-ring in the seal kit go?
The small O-ring is located in front of the plunger on the plunger retainer bolt.
How many seal kits are required to service one pump?
One seal kit is required per pump. A typical seal kit contains (3) low pressure seals, (3) high pressure seals, (3) O-rings for the seal case and (3) O-rings for the plunger retainer.
What is the part number for my seal kit?
Every pump has a seal kit available; seal kit numbers are item #300 on the pump data sheet.
My seals are very loose on the plunger, what does this mean?
Loose seals on the plunger are a sign of worn seals. Typical symptoms include water leaks or low system pressure.
Do I need a special tool to remove the seal case?
Pressure washer pumps typical do not need any special tools. There is a seal case tool for larger gearbox or belt driven pumps such as the 310, 340 and 350 (5 frame) or 530, 550, (7 frame), etc.
How many valve kits are required to service one pump?
Pressure washer pumps can take either one or two valve kits depending on the valve style. Pumps with a stacked valve design require one valve kit and pumps with a split valve design require two kits. This can always be verified by looking at item number #310 on the pump data sheet and checking the chart on the far right for the number required.
What is my part number for the valve kit?
Valve kit part numbers are located on the data sheet under item # 310. Be sure to verify the number of kits required before ordering.
Where do I look for damage in the valve parts?
Damage can occur to the springs or spring retainer, but most often damage is found between the valve and seat in the sealing surface between them.
What is the torque value for the valve plugs?
How do I disassemble the valve assembly?
A valve assembly can be disassembled by pulling it apart, in some cases using a small flat screw driver. Insert the screw driver between the spring retainer (plastic cage) and the valve seat and turn it slightly. The valve should come apart. The valve assembly easily snaps back together.
The valve and valve seat are discolored, can I clean them up?
Yes. Warm water with a mild detergent will work.