Why would I be getting 5 gpm out of a 8gpm rig?

Finally did a test on my pressure washer it 3000 at 8gpm. Takes me 52-55 sec to fill up a 5gallon bucket no matter what tip I use. I put a pressure gauge on it and and it was 3000-3100 psi and when I pulled the trigger it went down to 1500 psi. Talk to pressure pro and they gave me some suggestion but I wanted to see if any of you have come across this before. The tank is fed by a 275 gallon tanks and has never been run out of water.

sounds like you have the wrong tip on, if your pressure spike is 1500, that’s not right it should be only be 500 or so. Did you try filling the bucket with out a tip on it???

the pressure goes down to 1500 psi when I pull the trigger and yes Ive tried no tip and every color tip I got

Where are you putting the gauge?

How tight are the belts? If you press down on the middle of the belt how far will it move?

do you have the chemical injector installed??

No chemical injector while I was testing and gauge was connected right after unload and pump. Ill check the belts Micah didn’t think about that but would that cause me to lose that much water flow?

Check the pump. They may have installed the wrong pump.

ARC Powerwashing

when my belts were loose I lost pressure, my machine is a 3000 psi and I only had 2500 at the pump, and it still passed the bucket test with no tips…

What did pressure pros tell you???

What model# is the pump? Is the pump running smooth and consistent and not surging because if it is then you may have multiple problems such as air getting into the line. Also check the strainer to see if there is any clogs.

I would also check to make sure the rpm on the engine are set correctly

This is interesting. I hope Russ Johnson see’s this. I know that the RPM’s of the engine and the pulley size if it’s a belt driven Powerwasher does make a difference in the PSI to a pump but I’m not aware of it affecting the GPM’s of the pump. I’d like to know this myself because I can’t say for sure either way.

The pressure pro guys said check Rpms out also because the rig runs smooth. He said if that’s not it then I got to start taking the pump apart unfortunately. The thing is along 6months old which is the bad part.

Bret I purchased two machines at the same time both pressure pros, one of the machines rpm were set in-correctly from the manufacture,

How did you check it and how did you fix it?

Check your unloader?

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very easy to do, just get one of those gauges that wrap around the spark plug wire to tell you what your rpm are, then just adjust the govern screw until you get the rpm’s needed.

where is the governing screw?

when you pull the throttle look whear the cable is moving the arm their is a stop screw, that is the what I turned to allow greater rpm

Ditto on checking unloader. You could be bypassing your flow.