Nozzle sizing chart.
Nozzle Size for Pressure Washer
I have no idea what my nozzle sizes are, but my pump is rated to flow 2.5 gallons/ minute and my electric horsepower is about 1/3 of the original gasoline hp, I'm thinking ill need to run about a number 4 or # 4.5 orifice. I'll measure my current nozzle soon and may try and bore one soon.