Help with upgrading my pump

I currently am running a GX390 with a TSS1511 4gpm pump, and am really starting to realize how much 4gpm sucks on stucco/brick or basically anything that isnt vinyl siding. The most PSI I currently use is 800 according to my gauge when I have my rinse tips on, so Im assuming my motor can handle a bigger pump at this pressure. What do I need to take into consideration if I wanted to upgrade to a UDOR 8gpm 2500PSI (UDGC3017S)?? Both pumps are 1450RPM with 24mm right hand shafts, so Im assuming I can use the same pulley/belts as I have now? Besides larger inlet plumbing, will I just need to buy a new 1200-1500 psi unloader and the 8gpm tips from bob?

If you are going to get an 8gpm pump you will need a larger engine. First off every engine has a performance curve and a “sweet spot” keeping your small engine running smoothly and safely while trying to pressureruze an 8 gpm pump will be fun. S econdly you would have to match up your nozzles and unloder precisely and what happens when it fails? Third you may as well kiss any type of sidewalks and drive ways goodbye unless you only,just want to nuke everything.

My engine will still be running at the same RPM as it always does - 3600. It won`t be pressuring the 8gpm pump to its full capacity because I will have the correct unloader that allows the full 8gpm through but bypasses at around 1200-1500 PSI, and when I am on the trigger my tips will only let it pressure up to roughly 800. I understand my motor can’t run this pump at full PSI, but like I said I only need 800 to wash houses. This unit is strictly used for house washing, so I am not worried about any concrete work.

Do a search for your engine, there have been several recent threads that discuss upgrading the pump in great detail. That being said, you shouldn’t have any problems cleaning stucco or brick with the pump you have.

Im confused about what you are trying to achieve. Do you want more flow, or more PSI than what you currently have?

Even at 8 gpm you will not be able to have a strong enough mix downstreaming to clean brick and stucco. You will need to x jet it of direct apply chems.


Fatjoe is right, when i said you shouldn’t have problems cleaning those surfaces with your current pump, i meant you dont need more pressure to clean brick/stucco, you need stronger concentration of chemicals.


I am trying to achieve more FLOW. Rinsing my solution off stucco takes forever with 4GPM. I would be able to wash houses twice as fast with the 8gpm.

Also I should note that I live in a very dry area, there is no mold here. I clean off dirt/dust and cobwebs, so my mix doesn’t have to be insanely strong. I only need SH for the cobwebs and spider egg sacks, so Im thinking with 8gpm I could probably do straight 12.5 with elemonator, and if that isn’t enough I would just xjet.

It will definitely up the flow. You just wont have the pressure to clean concrete efficiently. Is there a dealer near you that you could double check the pulley specs?

Okay, yeah if you want more flow the most common upgrade is to a 5.5 @ 2500. I just did that with this engine, and it was very easy, although i went from direct drive to gear drive. Some people have went up to the 8 GPM 1750’ish with your engine, i think there have been a few threads on it.

Contact Bob at PressureTek, or Russ at Southside Equipment, and they will be able to tell you exactly what you need.

And thats fine as I do no concrete cleaning as of now, just want to speed up the rinsing process on houses. No dealers near here, however considering both my pump and the UDOR I mentioned run at 1450 RPM, and have the same shaft size, I am hoping I can use my existing pulleys.