I haven’t read this entire thread but the idea that a GX390 will wear out in two years is a little silly. I have two of them and they both have 4.5 GPM direct drive pumps on them and one is 10 years old and the other is 5 years old. I don’t use them everyday but they get heavy use in the peak season and with regular oil changes and tune ups they have never failed me. You could toss them every two years but I wouldn’t see a need for it. Put a tachometer and hour meter on it and you’ll see if it’s under performing.
Here’s a couple of pics of one I just freshened up and put a new pump on.
In my understanding, dialing it back shouldn’t change anything when you’re using low pressure tips for housewashing. Provided you set it up correctly, you will have the same GPM flowing through the same size nozzles, which will result in the same PSI at the gun and the same reach.
It also shouldn’t affect your draw rate from the injector, since it is the pressure differential before and after the injector orifice that generates the venturi vacuum.
The orifice will remain the same, resulting in same PSI before the injector. And again, the spray nozzles remain the same; so you have the same pressure drop after the injector.
Remember that Pressure is a function of Flow Rate and Orifice size.
steve just to clear things up i brought up the two year thing and said I replace my GX390 at two years of age as i can sell the old GX390 for $250 and by a brand new one for $800, As i find at 2 years of hard work they start to loose compression and a little bit of power and thats when i find you have to start to spend money on them such as rebuilds, coils, carbs and the like… No one said there worn out in 2 years i just replace them so all 7 of my rigs have new and fresh equipment all under warranty, some people i have sold 2 year old engines too are still using them 3 years later with little issues, just my personal preference
Yeah, I see where you’re coming from. I do all my own engine work since I’m a former helicopter mechanic and I can rebuild a GX 390 in a Saturday afternoon for a fraction of the cost of a new one. (An overhaul kit is less than $100) Also, If I wanted to I could put all kinds of upgraded parts on it to generate more hp such as a larger carb, different cam and bored over piston and so on, but I find they work just great as is. Do you actually check the compression or just sell them at two years no matter what?
Compression is checked quarterly, After 24 months they get put on the replacement list, we sell the ones that are worn out more than others, the better ones get replaced and we keep them as a spare or parts, On top of the 7 rigs on the rd in my area my business also has 5 franchises in other cities so we sell them cheap to the franchises if they want them and if not we just sell them online for $250. My big problem is the size of my business with 14 full time staff just at head office i dont have time to rebuild my engines like i did when we first started, As we systematized our business we found down time was the biggest way we lost money and by having this replacement system in place we have reduced downtime due to any engine issues to almost zero and the financial benefits are greater than the $550 per engine difference in buying a new engine every 2 years. Also since we by 5 engines at a time we get a 10% rebate back from honda NZ every year as well so pays of for us to do it that way.
You know what guys fuck this forum, pretty much all saying the exact same thing but cannot agree. Stubborn people especially the moderator and bystander. Where is the delete button, because i am not wasting my breath on you poeple.
@Carl_Nesseler, I was actually gonna comment on how I could see where you’re coming from: that a large, oversized motor working below its capacity may last longer than a small one at full capacity.
I’m still not sure that I agree with the hypothesis, since I’ve seen some small motors hum along very happily at the limits of their potential (like my last Toyota - golly that little 100hp motor worked hard pulling my equipment around, and seemed happier than ever at 225k+ miles…)
But this is what a forum is all about. Sometimes you present an idea that isn’t really accepted by the majority, and you can either reassess or reaffirm your own opinion on the matter. Opposing views generate ideas. Sometimes they’re not going to be expressed in the most tactful or eloquent manner, but this is a forum for power washers. Not everyone here has a phd, ya know…
If you still feel like you need a gentler group to rub shoulders with, I’d recommend Window Cleaning Resource | Community. It’s essentially the sister site to this one, but the community over there is uncharacteristically hospitable for a professional forum. And people do talk about power washing a bit over there, too.
I know that written text doesn’t always convey tone well, so I just want to clarify that none of what I’m saying is meant to be sarcastic or condescending.
It depends on your skill level and which rebuild kit you buy. I’ve rebuilt car and motorcycle engines so I’m pretty familiar with mechanical stuff. A basic kit is around a $100 but there are more complete kits for $200 ish which come with a new piston, piston rings, connecting rod, complete block, all the gaskets and a new crankshaft. I would call this an intermediate skill level job. You do need a torque wrench and a wide variety of tools. most difficulties come from trying to get things apart with rusted or frozen bolts/nuts.
