Powermate makes commercial and residential pressure washers. It sells a variety of power washers, from 1,900 cleaning units (CU) to 9,000 CU. A CU is a power washing industry term that relates the flow of the water to the pressure at which it exits the nozzle. Despite the wide variety in Powermate power washers, changing the oil in the pump is similar in all machines and shouldn't take you more than half an hour.
Turn on your power washer and let it run for a few minutes, then turn it off. This action heats the dirty oil so that it all drains out quickly. Locate the oil pan. For Powermate, it usually is between the motor at the base of the back wheels. It has a window on the side that indicates the oil level, as well as a bolt plug oriented vertically below it.
Insert your tub or plastic bin underneath the oil pan bolt plug. Cut off the neck of the bin or bucket if there's not enough room to place the bucket below the bolt plug. Use a razor knife to shorten the height of the bin.
Remove the oil pan plug, turning counterclockwise with a crescent wrench. Let the oil drain into the draining bin. Replace the draining bin with another as it fills.
Reinsert the bolt plug into the oil pan. Locate the oil cap near the motor on the Powermate and unscrew it. The oil cap looks similar to the motor oil cap in the engine compartment of a car, except smaller.
Pour in a few quarts of replacement oil. Watch the window on the side of the oil pan as the oil fills. Check your owner's manual for the specific amount of oil to use on your Powermate washer. Reinsert the motor oil cap and turn on the power washer for about 15 seconds, then turn it off. Remove the dipstick, which should be near the oil pan, usually closer to the handles of the power washer. Check the level of the oil and add more if the dipstick does not indicate Full.