The first thing you want to do is to check the inlet screen where you hook up the water hose. These will sometimes get clogged up and not let the water flow through it.
Also check the nozzle in the hose to make sure that it is not clogged.
If that is not the problem then the following answer is most likely correct.
Most of the time when this occurs you have to replace the entire pump.
These are very inexpensively built pumps and usually will cost more to repair them that replacing them.
What usually happens is that customers tend to put the pumps away without using the pump conditioner liquid in them. This causes the pump to corrode inside and the result is that the pressure relief valve inside the pump gets pitted and won't close. Also the corrosion causes other parts inside to not mesh together correctly.
These pressure relief valves usually are just a ball and spring type valve the will corrode the ball and/or the pump housing or the seating surface causing pitting, there for rendering it inoperable.
On a very few of these pumps, there are a couple of "PLASTIC" valves that will break... causing the pump to fail. These may be replaceable if you find the parts list. That doesn't mean that it will fix the pump, but is usually just about the only chance of saving the pump.
If this pumpsaver additive is added correctly before storage, you can usually prevent the problems you are having.
There is also a slight chance that if you add the Pumpsaver additive to the pump now and let it sit for at least two weeks, it might just loosen the valve. There is only a small chance that this would work, but it might be worth a try.
As much as I hate to give this kind of answer, it is usually the correct answer. Buy a new pump. In many cases it might be best to just replace the entire pressure washer as the new pumps usually cost nearly as much as the complete pressure washer..
Wish I had a better answer.
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