Karcher K2.91M nlets water in and out but won't

It sounds like there may be a potential issue with the pressure build-up mechanism in your Karcher K2 compact. The constant motor running without water pressure could indicate a problem with the pump or the pressure switch. I would recommend checking the following:

1. Check the inlet filter: Ensure that the inlet filter is clean and free from any debris or blockages. A clogged filter can restrict water flow and affect pressure.

2. Inspect the nozzle: Make sure the nozzle is not obstructed or damaged. A blocked or damaged nozzle can restrict water flow and affect pressure as well.

3. Check the pressure switch: The pressure switch is responsible for regulating the motor and water flow. It's possible that the switch is faulty or not functioning correctly. Consider contacting Karcher customer support or a professional technician for assistance with checking and possibly replacing the pressure switch.

4. Examine the pump: There might be an issue with the pump itself. It could be worn out, clogged, or experiencing other internal problems. In such cases, it's best to reach out to Karcher customer support or a professional technician for further diagnosis and repair.

Remember to always follow safety precautions and consult the user manual provided by Karcher for specific troubleshooting steps and guidelines.

Your pressure washer is either not fitted with a run/stop device in which case like mine you have to switch off within a few seconds of closing the trigger. Check your model features?
The humming noise is the motor stalled out against the pump because there is nowhere for the water to go. The shutoff is caused by the safety overload switching off after overheat.
Or, it has a pressure operated run/stop which is not working. Because water and electricity don't mix, I would suggest getting more specific help. You can download Karcher manuals /spares lists online from Karcher specialists but remember electricity is the silent killer.

This sounds like it had water left in it and it froze over the winter. The motot turning on and off signals a water leak on the output side of the pump. You may have a cracked pump housing. Locate the pump and make sure nothing is leaking in that area when under pressure. looh for fine hairline cracks.

Normally when you dry run a machine you damage the pump so it would probably need changing. The motor might be Ok but for you to fix it you will need to take it to a Karcher dealer/service center.

From experiance it sometimes can be more cost efficient to purchase a new Karcher machine and get the 12 month warranty than spending money on an older machine.

The motor is holding pressure in the line.
Check the manual.
I don't think it is supposed to cycle that much.
If it's not designed to do that, then there is a seal or a bearing that is leaking.
It's letting water pressure escape the hose by letting water seep back into the pump.
The motor is pushing more pressure into the line to keep up with the internal leak.
Two times a second seems like a lot, and the noise is probably annoying.
If the unit is new, take it back.
If it's doing the job, run the equipment until it dies, or else take it for repairs.

We had a similar problem with a paint sprayer.
Paint sprayers also hold pressure on a line, except the fluid is paint instead of water.
When the machine sensed a loss of pressure, it would cycle once to restore pressure.
After a while it was cycling constantly, just like your machine.
Working indoors with the constant noise was a nuisance.
I had the machine rebuilt, and used it for another year before buying a heavier machine.
I don't know if there is a business that rebuilds your equipment, or how hard parts are to find.

You did winterize the machine? Leaving water in a powerwasher will freeze and damage the pump. It's a common happening, because people don't think of it or are not told by the maker.

My karcher k 2.94 makes a loud screeching noise when trigger gun is pulled and released.... any idea what this may be ???

if the machine is blowing fuses then it could be the motor! if not then maby the start cupasitor has failed

Before you start it up:
1. Disconnect the high pressure hose 2. Connect the water supply and turn on 3. Make sure water is flowing through the pump
Start the motor, run for about 10 seconds and then turn off.
Turn off the water supply, connect the high pressure hose, turn water back on, start the motor and away you go.

Hi
don't know if this will help, but when I use mine, to start the pressure up I have to turn the nozzle to fine spray then turn it to the power spray and it works every time, shouldn't have to do this but I got it for nothing.