New to the party


Hello all, my names Jason Davis and I’m planning on starting my pressure washing business in the spring. First off I’d like to say am very thankful I found this forum, very informative!

For starting out I was looking at getting the DEWALT Honda GX390 4,200 PSI 4 GPM Belt Drive Gas Pressure Washer from Home Depot.

Is this a decent unit? I’ve read mixed reviews on it but wanted to stay with Home Depot so I can put it on my CC when they offer their special financing.

Reading it’s a belt drive pump but with a 1:1 drive with no reduction makes me think there’s not a huge advantage of going the belt drive over the direct drive. But again I’m a newbie so what do I know haha. Any feedback would be greatly appreciated!



Hey man. That is a great engine, and the unit can make you money, but for just a little more you can get one with a 5.5 GPM pump… which is what a lot of guys with the GX390 4 GPM end up upgrading to anyway. That’s what i did.

I’m showing $1300 for the Dewalt, and here is a belt driven 5.5 2500 for $1475.

Belt drive is always better than direct drive… several reasons why… mainly because it’s better on the engine, and it can easily pull water from a buffer tank. Direct drive sometimes has issues pulling from buffer. The third option is a gear driven pump, and those are about the same as belt driven… maybe slightly less desirable, depending on who you talk to.

I know you said that you were doing it through HD so you could use a credit card, but you might be able to do the same at pressure washing vendors… dont know.

The trade off for the increased water flow, is that the maximum PSI drops from 4200 to 2500, but the only time PSI is really relevant for us, is when doing concrete (or if you were running super long lengths of hose, i suppose). 2500 is sufficient for residential concrete, but commercial can sometimes require a little more… with 3000-3500 PSI typically being recommended for that type of work. Still… nearly everyone (if not everyone) says that the water flow upgrade trumps the PSI loss, because it speeds up all of your jobs (rinsing is what takes the most amount of time).

Hope that helps, keep searching and reading forums like this, and you will be fine come spring.


Thanks @tireshark appreciate the info!


Ill say it again we need a sticky section and this should be on it! haha


@MidWestWaterWays I read and understand that belt drive is the way to go but the 1:1 drive on this machine is what had me wondering if the belt drive model was still worth the extra $300 over the direct drive.

With the pump & motor both spinning at the same speed on the belt drive washer is lack of vibration from the engine really the only benefit? Only a greenhorn so not sure if I’m understanding that properly



That’s what I don’t understand… typically it says belt drive pumps run between 900-1400 RPM but this Dewalt belt drive pump In particular I was reading runs at a 1:1 ratio so it’s running around 3600 RPM therefore that would increase bearing wear, running temp & decrease life which to my understanding is usually the benefits of a belt drive over a direct drive

I guess I just wanted to see if other professionals on this forum have had success with this Dewalt machine or if I’m totally looking at it wrong haha my apologies.


Oh ok, I see what you are asking now. Where does it say that that is 1:1? I’m no expert, but that doesn’t sound right.


Simple to tell if it is 1:1…are the pulleys on the engine and pump the same size? Probably not…the one on the engine is probably less than half the size of the one on the pump.


Going off some reviews Ive read… Found the owners manual on line but didn’t see anything about it. May have to call DeWalt customer service to find out


I’ve read that Dewalt and a few others tricky like that. It’s a belt drive, but not really because their pulley setup does not reduce the rpm.


Different pumps are designed to run at different rpms… So if it is 1 to one that would mean the pump manufacturer wants it run at that rpm OR dewalt has the engines made with a different governor that knocks the RPM down or a throttle system that only lets run at 3/4 speed. For example my gas air compressor only throttles up to 3\4 speed to reduce wear and heat.


Hi Jay,
I am also new to power washing. Just finished my first season.
I would have to say that it really doesn’t matter about the 1:1 drive on the 4 @4.2K because if you like washing and customers appreciate your work, you will never wear it out because you will be so busy that you will upgrade to a better machine in one season and your first machine will become your backup machine in a year or less.
Just read these forums as much as you can and you will learn just about everything you need to know.