Pump issues

Hey guys, I’ve got a gx390 with an Udor pump and green spring unloader. Using a 25065 tip, I set the unloader until just a trickle was coming out. Then did a bucket test with the same tip (right?) and only got 2.5gpm. I’m also only getting about 25 feet of distance with my long distance soap nozzle (0040) No bueno. What did I do wrong? I have no leaks anywhere. I’m using a buffer tank. Please help! Starting to think I ordered the wrong pump…? Or the wrong unloader? Thanks in advance for any and all help.

Didn’t we already talk about this? Your supposed to set your unloader with the correct high pressure nozzle. What are the pump specs?

Yeah, you’re the one who told me I was using the wrong tip the first time. Ordered the right tip and used it to set the unloader. Here’s a picture of the pump.

That’s not the correct nozzle. Use a #5 or #5.5 to set the unloader. You won’t get 5gpm @ 3500psi with your 390. Use a pressure gauge and do a bucket test after setting your unloader to see what you get

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Max1 is correct… Use the proper tip for your PSI & GPM look for the nozzle charts.

When setting your unloader use the hose length you normally use.

Place the gauge closes to your pump

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I’m trying to get 5.5gpm at 2500 psi. That would require a #7 orifice, not 5. Or am I misreading something?

I don’t think you can get 5.5gpm out of a rated 5gpm pump.

To achieve the rated 5/3500 you’ll want a 2505 nozzle if I’m reading the chart correctly. Also, and I’m new(ish) to this, but is your gearbox at 1450rpm?

His high pressure nozzle should be a #5.5

His pump is a 5gpm Max I don’t think he can get more than 5gpm out of it. Some say you can get more gpm using a larger nozzle but I haven’t found that to be true…

I had that same pump before, great pump! It was paired to a Briggs 18hp… Beast!

You need a bigger pump

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Honestly I have no idea about the gearbox. I’ll check tomorrow

You can do pretty good with a 5gpm .5 isn’t that much more… Stick with it

I’ve had a 5gpm for a couple years…I like ‘em. Trying to dial in this pump is more work than it should be though! Lol. I’m just new and still learning.

Post pics and ask away!

What other pics should I post? The pump works great. Well, other than that it’s only producing 3gpm lol. I ordered a #5 orifice this morning. Maybe that will be the solution.

Try just using no nozzle at all in a bucket and see if it puts out 5gpm that way, straight out of a wand or gun.

Post a picture of the way you have a plumbed…

This is before I replaced with the green spring unloader.

Can you post a current picture?

Looks to be plumbed okay, There could be some corrections however. Be sure that you are hooking up to your unloader correctly. Bypass, Inlet, Outlet… and prime the pump for a few minutes, sometimes air is trapped inside, lastly… have you ever throttled your machine down?

Sometimes people lower the rpms on them and then you don’t get the 3600 rpms you should be getting resulting in poor performance.

Thanks for the input. I figured it out! Well, the folks at Udor figured it out. Udor rep suggested force feeding it with the garden hose and it worked perfectly. This thing is a beast! It’s got to be putting out more than 5gpm. Doing a bucket test later. So the culprit was the buffer tank. I’m guessing because it’s gear drive it doesn’t pull as well as belt drive?

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