I have a gasoline pressure washer. i connect machine the right way. try to start but machine only runs when trigger is pressed. stop pressing trigger machine shuts off. the water is flowing through the hose, but looks like there is not alot of pressure building up.

This is normal. The high-pressure car washer has certain dangers. If the water column of his spray gun is aimed at people, it will stab people. If the switch is turned on and spray water, then the pressure of the spray gun head will be sprayed around, which will accidentally hurt people. people, so it's designed this way.

If you are using a water tank for water supply, remove the water supply line from the pressure washer and connect a water hose from a faucet. Turn the water on, then crank the engine. Pull the trigger of the spray gun until water comes out. When then water starts to spray properly the release the trigger, shut engine down with pressure on the line then reconnect the water supply from the tank to the pressure washer. If this fixes the problem then the problem was "air-locked"! Happens alot with new pressure washers that have never been run. If you need any other help, please email me @ [email protected]

Disconnect hoses.
Look for kink in water hose.
Check incoming water connection for filter washer
Replace filter washer
If you don't have a filter washer, put one in.
Hook up water, and turn on
Water should come out other side of pump.
Turn on machine.
Do you get pressured water out of pump.
If no pressure, then pump is suspect
Hook up washer hose without gun
Does pressure come out of washer hose
Finally, the gun trigger may be bad.

We had to buy guns now and then.
Search for pressure washer guns
Following link shows guns we used:
http://www.ultimatewasher.com/pressure-washer-trigger-guns.htm

The issue you are having is with the unloader valve in the pump. Now with the 520m it is a little bit harder to repair than with more gasoline powered pressure washers but it can still be done. It would be easier if I could just send you a email of the breakdown on the machine. Send me a email to [email protected] with the discription of the problem you are having.

spill valve is stuck and needs to be cleaned and greased common problem....also check all connections for blockage in line

HI Your machine wil start and stop if you have any external leaks when the machine is running at not pressing the trigger. Please start the machine and not pull the trigger and look form leaks. A common one is around the high pressure hose outlet and also the trigger.

Check the pressure washer for leaks. That sound is probably the unloader valve recycling as the machine slowly looses pressure and needs to build it up again to max pressure.

Got gas?

To determine if your problem is due to an easily replaceable part, follow these steps:

1. Connect the water supply hose, the pressure hose, and the wand WITHOUT any nozzle tip.

2. Turn on the water supply, and press the trigger until water is smoothly running out of the nozzle
after any air is all purged out. Release the nozzle trigger.

3. Start the engine, and let it warm up for about 30 seconds.

4. With the engine running smoothly, press the nozzle trigger. The water should flow out of the nozzle (without the tip installed) at a faster rate, while the engine noticeably loads down as it used to do before your "no pressure" problem. If it does not load down, turn it OFF, and disconnect everything, and contact a Karcher repair facility.

5. If the engine does load down, release the trigger, and install one of the nozzle tips (not the black one).

6. Press the trigger, and the engine should load down, and you should have normal pressure from the wand. After you release the trigger and press it again, you will probably again have no pressure, and the engine will not load down. Removing the nozzle tip, pressing & releasing the trigger, and re-installing the tip should give you normal pressure again, but releasing the trigger will cause no pressure until you again remove the tip, press the trigger, and re-install the tip.

This is caused by a bad UNLOADER VALVE, which is located under a black cap with a metal button on it located on the top front of the pump. I don't know if you can purchase the replaceable parts from a Karcher repair shop, but when a neighbor & I took his washer to a repair place, it looked pretty simple to do this repair, and he was charged about $60 to replace about a $5 (maybe) part, and it took about 5 minutes.

pressure washers has this pressure switches where in as you press on the trigger, the washer works and if you release it, the pressure would build up high and it would trip this switch to turn off the motor or deflect the water to the by pass hose ( if the motor is not stopping) then as you press again the trigger, water should come out of the gun again but would not,

i have encountered the problem is in the pressure switch, even the pressure went down, sometimes it wont close the contact then the motor wont run ,

if the motor is continously running, then the trigger switch is the problem, the pressure excerted on the switch is so high that even if you press it , it won't open up to release the water.

what i can suggest is to tie the trigger in the gun so that it is always pressed and then just unplug the unit if you want to stop using it. it is an inconvenience but it will work.

or, open the gun and see if you can figure out why pressing the trigger would not open the switch.

another option is you can lower the pressure of the washer if it has an adjustable pessure controller. by lowering the pressure might open the switch when ever you press the trigger.

i hopw i was able to fix...

good luck,

drcool