Best pump... AAA or Cat?

I am thinking about building my own pressure washer. in regards to the water pump, I have seen different opinions on both brands (AAA & CAT), so I thought I’d probe the group here for your opinions. I know there are likely manner other brands, but it seems that most of the mechanics out there like the CAT, but why would Simpson place a 5 year warranty on the AAA pump and only a 2 year warranty on the CAT pump (found this in the operators manual of one of their pressure washers).
Also, I want to use the Honda GX390, but for the cost difference and the fact that I’ve seen too many pro’s recommend the Predator line of engines, it almost makes sense to save the $300 and put that towards some other goodies.
So please, tell me your thoughts… I’m ready to read :wink:

Any particular reason you have it narrowed down to those two?

marinegrunt, what you read was an errant post that I did on my phone…arghh… however, the post is still pretty much the same with just some more fluff… but, tell me what you REALLY think, Lol.

Udor is the best pump out there. I would also stick with Honda. It’s far superior compared to Predator. I’ve ran predators on stuff around the house and they’re hit or miss. I’ve had the bad right out of the box and have had one on a tiller for years. If you have the money buy quality upfront. The difference in cost between a Honda and Predator is only one or two house washes. I have nothing against Predators. One of the only reasons people buy them is because with the warranty you’re able to exchange for a new engine, buy a new warranty, and repeat. The store managers even tell you that.

As far as pumps I would go with an Udor or General.


Both are a turd, but a CAT over a AAA any day.


Gotcha on the engine stuff… I’d much rather have the Honda anyhow. I’m going to try and find me a good used one and if not, I suppose I will plunk down the change for a new one.
Why would you choose an Udor over a CAT, or even a General? If you don’t mind, tell me why you would buy either one of these or maybe reasons NOT to buy one.
I did a quick search on the Udor pumps and surprisingly enough, I found one at for just under $400 (4gpm/4kpsi). That is quite a bit less expensive than the CAT and I haven’t done enough research yet on the AAA or General pumps.

+1 on Udor, I have one and it’s built like a tank. I have a General for the backup unit as well, and no complaints on that one, either, but I’ve heard that Udor can stand up to abuse better.

Either way, if you’re building one for professional use, then you want a gearbox or belt drive. Gear drive will be easier to build on your own. You’re looking at around $600 for a 4GPM Udor pump. Sprayer Depot is great to deal with and their pricing is probably hard to beat. I got my Udor from them.


Next question is… I have a general understanding of what the unloader valve does, but for the sake of not making a mistake in selecting a particular pump, I need help in grasping what is really going on with this valve. I noticed how some pumps have what appears to be a physical unloader valve on the pump and others, such as the Udor pump I’m looking at now, DON’T. What is to prevent this particular Udor pump from burning up in the absence of this valve (keep in mind, I’m admitting quite a bit of ignorance here, as I “think” it has one). It’s quite possible the valve is there, but does not have the same physical appearance or maybe function as the others. In essence, I’m going to want to be able to release the trigger on the gun and not have to worry about my pump burning up. I know my current DIY grade machine just circulates water so I know better than to leave the machine running for more than 30 seconds without trigger press. Long story short, does this particular model Udor pump (ML4.0/30-W) give me the ability to run the machine without the trigger pressed? Will I need a buffer tank? What else might I be in for a surprise?


Ok…you want an unloader that is separate from the pump, not built-in. You also want what’s called ‘fully plumbed’ so bypass can be sent to a small buffer tank when off the trigger. The machine can run all day like that.

A 4/4 machine only needs about a 20 gallon tank, don’t bother with anything big.

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For the sake of simplicity avoid any pump with an unloader that’s built into the body of the pump, they are mass produced gimmicks and not worthy of a serious discussion.

Honda motor and CAT pump is a excellent choice I run that same combination everyday. Not that I want to have this debate again.

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What’s the difference between a direct drive and gearbox pump? For sure probably the cost, but what else? Why wouldn’t a direct drive version be a good choice… be the devils advocate LOL.

Belt or gear drive runs at lower rpm, operating temperature, resulting in longer life, more suitable for commercial use. Also belt and gear drives can draw water from buffer tank which is also a big benefit.