New guy, lurking

Hey gang!
I’ve recently discovered this site and enjoy reading/learning from each and every post.

A little bit about me.
They call me PuJo around these parts. I am a life long oil field worker in the Gulf of Mexico.
I work a 14 on and 14 off rotation. Having 14 days off at the time, I have been cutting yards, bush hogging, and whatever else I could find to do around the area. I was looking for a pressure washer to buy for personnel use and thought that maybe is I get one big enough, I could make a few $$ at the same time. Well, that was before I found this site and made the purchase. I ended up with the SIMPSON Cleaning ALH4240 Aluminum Gas Pressure Washer Powered by Honda GX390, 4200 PSI @ 4.0 GPM. If I would have found this site prior to my purchase, I would have went with a belt driven unit.

Oh well, I guess I will just have to learn on it and build it up to an upgrade!

My goal is to have a second (third) job power washing homes in my area as well as building a trailer to haul it all around on. I am not a fan of the pick-up truck skid.

There is only a couple people power washing in the area and it seems like I could do well with it here in the central Louisiana area.

Anyway, I can ramble on but that’s enough for now.


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Hi, welcome to the PWRA.
Keep on reading, best investment you can make right now


You have the same exact machine I have! It works fine as a starter unit, no worries.

Oh, and it runs fine off a buffer tank despite being a direct drive, despite what some may say.


That’s good to know!
I was kicking myself for purchasing before researching!
Any idea as to how much suction pressure this pump has when running a bulk tank?


Zero. No suction at all, it has to be gravity fed, but it will work, has been for me for years.

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Sounds great, I may have to look into a bulk tank for those bad water areas.


The buffer tank is to cool the pump and doesn’t have to be too big.

A supply tank (for bad areas) needs to be bigger.

Generally speaking, you can run a 4GPM from the hose all day long with no need for a water tank.

However, a small buffer tank will allow you to be off the trigger as opposed to not having one and then only having a minute off the trigger.

Bigger GPM machines need a large tank and combine buffer and supply in one.

Reading and learning, if my thinking is correct, when you say “cool the pump”, you are referring to plumbing the unloader valve to the buffer tank? If so, my Simpson ALH4240 Aluminum Gas Pressure Washer/GX390 doesn’t have an unloader that I can re-plumb. So is that something I would have to replace with a different style or something?


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Ahhh ok, sorry, I’m not familiar with that model - I went off the GX390 and assumed it would have a separate unloader, but it doesn’t :blush:

So you can use a tank, but can’t be off the trigger for more than a minute once it’s warmed up.

Generally speaking, the pump will blow before the engine does, so next pump needs to have a changeable unloader :+1:t2:

No knowing much about the industry, is there another pump recommended for the GX390?

A gear drive Udor or General pump are popular bolt-on options. Upgrade to something that’s 5 or 5.5 gpm

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Just be careful balancing gpm and psi, jump up to 5.5 with that 390 and you’ll only get about 2500psi or less, so no bueno for concrete cleaning.

There really needs to be a 500cc motor, would make a fantastic mid model washer.