DeWalt pressure washer

[PTmowerMech]

Dewalt DXPW4240 pressure washer with the 11.6GA13 pump. Runs fine with the trigger pulled. Let go of the trigger and it dies like the unloader is stuck. The 2nd time I started it, (before checking the unloader) it built up so much pressure that it blew the brass fitting for the soap hose So I remove the unloader and it still bogs down and dies?
Now a lot the pressure comes out there. From the looks of it all, 130, 131, 120 and 121 blew out.
Note: I usually only work on the engine side of these. So I don't have a pressure gauge.

But I guess the main question is, if the unloader valve isn't stuck, then how could this build up so much pressure that it bogs the engine down. (Honda GX390)

 

[ILENGINE]

I would say you have an unloader issue. Either a split/nicked O ring in the 104 series, or the passage*looked like small drilling coming off of the side of the fitting where the unloader screws into) from the high pressure side/high pressure hose fitting to the unloader is clogged. The unloader isn't going into bypass mode.

 

[Hammermechanicman]

ILengine is right. Unloader problem. Take all the 104 assy out and check the passages. If passages good probably bad unloader.

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[PTmowerMech]

I would say you have an unloader issue. Either a split/nicked O ring in the 104 series, or the passage*looked like small drilling coming off of the side of the fitting where the unloader screws into) from the high pressure side/high pressure hose fitting to the unloader is clogged. The unloader isn't going into bypass mode.

That little hole (I think) your talking about was clear. I blew air into it, with it wrapped in a plastic bag, and didn't see anything come out.. And from what I can see, there's nothing in the hole. But, I'll re check it and look for bad O rings.

BTW, the nipple is free. But doesn't go all the way up (til it's flush with the hole) Maybe it's sticking 1/2 way?

 

[tom3]

Is there adjustment on that?

 

[PTmowerMech]

Is there adjustment on that?

On the unloader? Yes, there's a handle that turns on top of it. I was about to loosen it, when the soap connection blew out. Now, so much water comes out of the soap hole, that I don't think turning the unloader would actually adjust anything.
I'm just guessing here. I've only worked on the engines and replaced a few pumps.

 

[ILENGINE]

If the soap connection blew off most likely the ball and spring are now missing. Most people loose the ball when they remove the connection. and with it blowing off under pressure I am sure those parts are gone.

 

[PTmowerMech]

If the soap connection blew off most likely the ball and spring are now missing. Most people loose the ball when they remove the connection. and with it blowing off under pressure I am sure those parts are gone.

The diagram doesn't show it having a ball.

 

[Hammermechanicman]

145 is the soap injector. 131 is the over pressure relief valve. It blows out to protect the pump. 104 is the unloader and 91 is the pressure regulator.
You have a blockage in the system somewhere at the pump outlet

 

[PTmowerMech]

145 is the soap injector. 131 is the over pressure relief valve. It blows out to protect the pump. 104 is the unloader and 91 is the pressure regulator.
You have a blockage in the system somewhere at the pump outlet

I see what you're saying. In fact, this may not be the correct diagram. Because the part that blew out, had a nipple and the hose connected to it, which was in the exact spot as 121.

I'm about to head to the shop. I'll compare this diagram with the one there, and report back.