Craftsman Pressure Washer - 2 issues

Machine Repairs
1

Hi!

  1. I just replaced the pump head on my Craftsman gas pressure washer (model #C950.672153 with a Honda GCV160 motor) with a RMW2.2G24 pump with this item from Amazon: Pressure Washer Pump Head Aluminum Compatible with SRMW RMW Series Pumps 2.2G24 2G20 2G24 2.2G26 Amazon.ca

It has a black part on the new pump head that I believe is called a thermal relief valve. I installed the new pump head and water drips out of the thermal relief valve… is this normal? Does this black cap pop off or is it supposed to stay in place? See attached pic - part circled in red.

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  1. My new pump works good but the motor stalls instantly after releasing the trigger handle. Why is this? Is it an unloader issue? I believe the same stalling problem happened with the old pump head. Should I adjust the new unloader?

Thoughts?

2

Picture of my Craftsman pressure washer:

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3

Most members on this forum are professionals using commercial machines, so you may not find much help for your type of pressure washer.

It sounds like the unloader might not be bypassing when you release the trigger, causing the engine to bog down and stall. Have you adjusted the unloader and set it to the correct pressure using the proper tips? That would be the first thing I’d check to address the engine shut-off issue.

Regarding the leak from the thermal valve, it might be a case of “you get what you pay for.” The valve shouldn’t release water unless your machine is overheating. It’s a safety feature designed to open when the temperature gets too hot for the pump, discharging the hot water to cycle in new, cooler water. Since it’s a no-name brand, the leak could be due to lower quality control.

4

This forum is mainly for commercial machines and companies, but I suspect you need to adjust the unloader.

1 Like
5

Thanks for responding, I wasn’t aware that this forum is mostly for commercial pressure washers. Any tips on adjusting the unloader?

Brand new pump and it leaks through the thermal release valve. Is it leaking becauee of the excessive pressure caused by the unloader?

Thanks for the help!

6

Yep it appears so… any tips on doing so?

7

Ton of videos on youtube showing how to do it.

Basics for a pressure trapped unloader:

  1. put a pressure gauge between the pump head and pressure hose
  2. turn unloader down to lower the psi
  3. start up machine and pull trigger and release any air
  4. put in the properly sized tip for your machines GPM and PSI
  5. pull trigger and see what the reading on the gauge is
  6. let go of trigger and adjust unloader a 1/4 -1/2 turn
  7. pull trigger again
  8. continue steps 5-7 until you reach the appropriate PSI for you machine
  9. aim to get only a few hundred or less spike when letting off the trigger
  10. lock down the unloader if it has a nut and never touch it again
8

Sometimes you have to replace them thermal release valves, if water gets hot in the pump it opens up to release warm water and introduce fresh cool water in.

9

Everyone,

I have discovered a couple of things:

  1. The unloader was not very tight at all - I snugged it up.

  2. The adjustment set screw on the unloader was screwed all the way in (it was that way when I bought it off Scamazon), I backed it out one turn.

The pressure washer now doesn’t stall when the trigger is released. It does drop in rpm somewhat but not much. One problem solved.

  1. The thermal release valve was also a bit loose too… I tightened it up and it doesn’t appear to leak anymore.

Easy fixes, thanks for the help gentlemen.

3 Likes
10

Hello. New to this forum. My Simpson pressure washer engine (Honda) recently started to stall a few seconds after releasing the wand trigger. I replaced the unloader valve, but the engine stalling problem continued. I backed-off on the unloader spring tension one complete turn. The engine no longer stalls when I release the wand trigger. However, the engine rpm does not noticeably change when releasing the wand trigger. Is this normal (acceptable)? Thanks

11

Did you properly set up the new unloader with a pressure gauge?

12

Unfortunately, no. I do not have access to a pressure gauge. Winging it. Thanks for your interest.

13

Hello again. I now have a pressure gauge. My pw is a Simpson MS60921 advertised at 3,300 psi and 2.4 gpm. Presently, I am at 2,600 psi (trigger open) and 3,200 psi (trigger closed with a 25-degree tip that came with the machine. I am hesitant to raise the pressure any higher with the current pressure differential. Should I expect to get 3,300 psi from this machine? Is the 600 psi differential acceptable? Any advice is greatly appreciated.

14

You can’t raise the pressure by adjusting the unloader to be higher when off the trigger. That rating is just the max the pump can do, not what the machine will actually put out when using it. You have 2600 psi homeowner grade machine.

15

Thanks for your response.