I had a POS Simpson 60843 with a AAA triplex pump that died. I attempted to repurpose the 13hp (3600 rpm) motor onto a skid with a 2-3/4" pulley and matched it with a 6" pulley on my Dayton 1MCY1 (1450 rpm) Pump. This setup should produce about 3000psi at about 4.5gpm. Got it all plumbed and did a bucket test and only got about 2gpm. It appears that the motor shaft is turning much slower than it should; do they have internal gearing for motors that are paired with direct drive pumps? I used a tach and the motor is running properly. Any ideas before I go out and buy a gx390?
Describe how you did a bucket test
I ran the machine for about 5 minutes to warm up; then redirected my 50’ hose with the ball valve open and measured the water output over a minute in a bucket.
Did you feed it off of a buffer tank? Unloader set correctly? Belts are right? Ball valve?
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Came off my 100 gallon buffer tank, 1" all the way from the banjo to the pump inlet. Unloader was set, using 3vx belts, tightened properly, no slipping. I took the belt guard off and you can see that its not spinning fast enough; I just have no idea how I’d measure that.
Hook your machine up strait to your spigot and see if you get better gpm. If your machine was starving you’d definitely hear it.
Hooking a 5+gpm machine to the wall wouldn’t be the best idea here in Florida; most houses only push about 4.5.
You said your machine should be putting out 4.5gpm… I meant to test it to see if your problem may be with your tank set up
Can you post a few pictures.
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The pump is rated 5.5, I went conservative with the pulley ratio. Not worth chancing it running off the wall IMO. Thanks for the suggestion though.
But you’ll leave it running off your tank long enough to do a bucket test knowing you’re clearly not getting the right gpm? 
Is the pump new? If you take the belt off does the motor spin faster. I m sorry but I do have to ask if which pully you installed on the motor. It sounds like you are are spinning the pump to fast
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I think you are missing the entire point of this post. Its obviously not a water issue; it has to do with the rpms of the pump.
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I just came inside from taking pics. Ha, the 6" is on the pump. The pump is brand new
You have the wrong pulley on the motor. I think you are spinning the pump to fast
The larger pulley is on the pump; it is almost exactly a 2.2-1 ratio. I don’t see how that could be too fast. 6" pump, 2-3/4" motor
Throttle wide open?
