Outdoor Power Equipment and Small Engines - new 3400psi, preasure washer low preasure?

About 6 months ago I bought a discontinued display model never used craftsman 3400psi, 4GPM, 11hp B&S OHV engine preasure washer. I made sure the water is on before starting. It doesn't seem to have a whole lot of water preasure like the other similar preasure washers I've used before. The engine is running fine and starts on the first pull. I have adjusted the preasure regulator to maximum, low, medium, back up to maximum. It doesn't have the water preasure that it should have.

I am using a quality 100' water hose but I don't know the inside diameter off hand but it is not those cheap small diameter hoses. Any help or suggestions would be greatly appreciated. Thanks in advance. dave

Is it getting 4GPM? Have you run the water through the pump, engine off, gun open, to get rid of any air trapped in the pump? You can tell when the water stops cracking as it leaves the tip. Check your water inlet filter, to make sure it's not obstructed.

I had the water running through the gun as there was no air comming out. I understand what you mean about having air in the system. This was a display model and when I bought it there was no gas smell in the gas tank leading me to believe it was never used or run. I am guessing there is a problem with the pump. I do see the shaft turning going to the pump. Is it possible the shaft may not be connected or engauged to the pump. Thanks for your help. dave

Dave,

Turn on the water pressure and depress the trigger without the motor running and note the flow then start the engine and see what you get.
This will give you some indication of what the pump is doing.

Another thing to look out for is that if your unit has soap injection, there will be a low pressure/high volume nozzle to use when you want soap.
Is there a chance you have this nozzle on the wand?

Greg, I probably won't be able to run those tests for a few days as I'm getting ready to leave town to cut trees for firewood. When I test it I will post the results. I tested only two of the high preasure nozzles. I didn't use the low preasure nozzle to use for soap. The brass soap fitting attachment is connected in between the preasure hose and pump. Is that ok to leave that there if I'm not using soap. Thanks for your help. dave

when you post the test results please indicate the pump mfg and model. this will help in diagnosis if you don't get anywhere. i've rented these things for 25 years and air has never been an issue. note pump type, triplex plunger or axial, belt driven or direct drive, etc. dumb question, is the throttle up ?