My new machine is 5.5gpm with a Honda 390, 13HP motor. Is this motor too small (ideally) for this size machine? I can’t get a good draw from the downstreamer and I’ve eliminated all other potential issues, so I’m wondering if this may be the issue…
What pressure are you running at, or hope to achieve?
It’s rated at 3000. This is my first large machine so I’m not familiar with adjusting the pressure. I’ve been using it as I purchased it.
Who sold that to you? You defiantly exceeded the physical limitation of the motor; working the pants off it.
http://www.generalpump.com/PDFs/TECHNICAL%20DATA/ServiceManual.pdf
Under electric HP requirements, in footnotes, electric to gas conversion is 1.8 times more.
6GPM @ 3000 PSI according to the charts needs 22.68 HP gas engine
5GPM @ 3000 PSI, 18.9 HP gas engine
so 5.5 ,3K 20.79 HP
I really like the Honda motors, I inherited a GX660 with 5000 running hours.It was in a good environment overrated for its demand, always had oil changed. adjusted the valves, has 7000 running hours still running strong.
I got it from a local supplier in my area. I went in for a 4gpm at 4000psi machine (with a 13hp motor) and ended up getting this one for about $200 more.
So will lowering the pressure avoid decreasing the life of the motor? What can I do to ensure I get the max life from the motor?
I bought this machine brand new in this configuration.
Then you should return it. Or demand a bigger motor or the 4GPM pump.
So a few days after I got it, i stooped at another shop to get a valve and they told me the very same thing that you’re telling me now. So I immediately called the shop that I got it from and wanted to return or exchange it, but they said they don’t do either. So I proceeded to tell them what the other shop said, and they convinced me that the setup I bought was perfectly suitable, even standard. But even if it was swapped out to a 4gpm pump, according to the chart you posted, 4gpm at 3000 psi still needs at least a 15 hp motor.
Yes its not ideal, but it can be done. it will work the motor to death, you could get maybe 1000 hours. yes its pretty common to buy 13HP 4GPM, 3000-4400 psi units.
Honestly I would just bit the bullet and buy a 20 HP motor, Harbor fright sells one for $600, but I would get a Honda GX660.
With proper care, a 5.5GPM with a honda can last 5000 hours. I have another with 6000 hours (just motor hours, replaced pump seals and valves, controls, ETC).
I really like having a local dealer, your going to have breakdowns. time is money, and my local guy stocks the parts, quick turn around.
It’s just odd because pressuretek sells 8gpm at 3000 psi machines with gx630 motors which only put out 20 hp. But that chart says that such a machine needs a 30 hp motor. I’m so confused lol.
Its just a guideline, the less the motor has to work, the longer it will last. At some point, your going to exceed the limitation of the motor. 5.5GPM @ 3k with 13HP, your going to need more motor.
So the less motor, the less the life basically…
Its physics: 13HP can only move so much water. if you ask more of it, its not going to put out anymore,
I got it. Hell, I may use this as a reason to go get an 8gpm, lol. Thanks for all your advice.
But could this cause the injector to not pull properly?
I don’t use soap injectors. I would imagine they work on vacuum draw. With some flow, your should have some vacuum. I don’t know if you have to size your injector to your pump. Are you getting any injection? looking quick, it looks like a simple spring check valve, could break easy. I’m not the guy to ask about that, hopefully someone else weighs in.
to answer your previous question;So will lowering the pressure avoid decreasing the life of the motor? Yes, you could even make your 13 hp work at 5.5gpm but at 2000 psi or hell, 1000psi for long motor life.
