Craftsman 3100 2.8 GPM Pressure Washer pump erratic

[fairlaniac]

I've had the washer for about 3 years. Used it maybe 5 times. So the other day I go to use it. Starts up a little rough but runs. After 5 minutes the engine cuts out. Now it will only run on full choke and it's slow and rough. So during this troubleshooting I shut the water down as I try to get it to run. Occasionally running a few seconds to a minute with the water off. Anyhow it won't run so I put it away until I had time last night to deal with it. I took the carb apart and there are ant carcasses in the fuel bowl, inlet ports, etc... So I clean the carb up and clean out all passages. Put it together, drain fuel tank and clean it. Add gas and it runs like a champ. However the pump will pump for a few seconds and then it stops as the water comes out with a stream of pressure. Then it pumps and stops, pumps and stops, etc... So I figure it's the pump but is there anything I can do? Engine stuff I have no problem troubleshooting but the pump is something I've never dealt with. Can I fix the pump or must it be replaced?

Thanks!

 

[BillK]

make sure the screen in the inlet fitting isn't half clogged. It will cause weird issues.

 

[fairlaniac]

Screen is clean. Here are two videos of it running. The first video is a complete uninterrupted squeeze on the gun. The second is me letting go of the gun when the pressurized water stops. There is a weird vibration noise right before the pressure build after letting go of the gun?

 

[Fixin'Stuff]

Mine does that when there is air in the garden hose supplying the pump. Once I get all of the air purged then it works fine.

 

[bmxdukie]

Never run a pw without waterflow. You will burn out the seals on the pistons in seconds.
Especially on cheap units that department stores sell.
So you likely need new seals.

 

[fairlaniac]

Mine does that when there is air in the garden hose supplying the pump. Once I get all of the air purged then it works fine.

Thanks - air was purged from hose.

 

[fairlaniac]

Never run a pw without waterflow. You will burn out the seals on the pistons in seconds.
Especially on cheap units that department stores sell.
So you likely need new seals.

Thinking that might be the case. Any exploded views of the pump anywhere? Or are they pretty self explanatory upon disassembly?

Thanks!

 

[Fixin'Stuff]

I've seen YouTube vids of how to rebuild the pump. Doesn't look difficult.

 

[fairlaniac]

So today I took the "head" brass with seals, o-rings, etc... off, took everything apart. All seals look new, o-rings look new, everything looked good. On the main body the pistons all reciprocated when turning the shaft adapter. It looks new inside but then it should for the handful of times used. So I hook it all up and it will run well for a few minutes and then you can hear the tone of the engine/pump change as the water loses pressure. Once I let go of the trigger the pump seems to kick in and I have pressurized water. Sometimes it runs for seconds, other times for minutes. Any other ideas?

Thanks!

 

[Toolman_Johnny]

So today I took the "head" brass with seals, o-rings, etc... off, took everything apart. All seals look new, o-rings look new, everything looked good. On the main body the pistons all reciprocated when turning the shaft adapter. It looks new inside but then it should for the handful of times used. So I hook it all up and it will run well for a few minutes and then you can hear the tone of the engine/pump change as the water loses pressure. Once I let go of the trigger the pump seems to kick in and I have pressurized water. Sometimes it runs for seconds, other times for minutes. Any other ideas?



Thanks!

Sounds like a sticky unloader valve to me. A pretty common issue on less expensive PW's that can happen when the pump is not fully drained and cleared out (I use compressed air to clear mine) after each use.


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[bowhuntr311]

Sounds like a sticky unloader valve to me. A pretty common issue on less expensive PW's that can happen when the pump is not fully drained .......

Ditto what he said ^^^^^

Pretty common to have replace unloader valves in them.

 

[fairlaniac]

Took the unloader valve off, disassembled it completely, nothing appeared damaged but the lube seemed thick. Cleaned it up, re-lubed it and assembled it. Works perfect now.

Thank you all for your assistance.

 

[Toolman_Johnny]

Took the unloader valve off, disassembled it completely, nothing appeared damaged but the lube seemed thick. Cleaned it up, re-lubed it and assembled it. Works perfect now.



Thank you all for your assistance.

Excellent. Glad to hear. It's a good idea to always drain it well and blow the pump out (using compressed air) after each use. Cheers.


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