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I have a serfas fp200 floor pump that no longer pumps air. The piston goes all the way down with no resistance, so no pressure develops. It's not the hose.

Posted by Eric Hayashi on


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John Trevino

  • 1420 Answers

SOURCE: Low Pressure

I worked at a tool rental while attending college and had the opportunity to work on a variety of pressure washers, however, they were of the commercial type. Commercial washers are slightly different in that they usually have seperated components for easier service. Attached to the pump by fittings or rubber hose were the pressure regulator (which has the bypass unloader inside), chemical injector, pressure gauge as well as the hot water release safety all external to pump. Your pump has all these components in one case. By far the most troublesome component is the pressure regulator/unloader which when failing will result in low pressure because it will bypass water back into the intake as you suspect is happening to yours. Here are a few things to check. I believe that your pump is 2500 2.4 gpm. Test gpm water capacity by running pump normally with hose and proper tip attached. Spray water into bucket for one minute and verify that you are pumping 2.4 gallons of water (or what ever gpm your machine is rated). Measure the amount of water that your machine delivered. If it delivered proper gpm and pressure is low then problem could be worn or improper tip. The pressure is created at the tip and pressure will drop as the tip wears. As the unloader/bypass wears, water will bypass at a lower pressure. (Try lowering the pressure regulator all the way ) If water measures less than rated delivery than the machine is bypassing water due to worn regulator/bypass, checkvalves pitted, oring in front of checkvalve worn or cut or missing, or body of pump where checkvalve/oring seat is pitted allowing water to leak past valve. The cap that is removed to access checkvalve must presses against checkvalve with enough force to prevent water from leaking thru oring and body of pump. Examine checkvalves and orings with maginfy lens and look for pitting. Valves surface and orings must be very smooth and tight fitting to work properly. Body of pump where checkvalve oring snuggs against must be very smooth. Any surface where oring seats must be smooth. As water bypasses it cuts metal and orings just like a leaking faucet so look for cuts in metal and rubber. This info and my experience is better suited for larger pumps and higher pressure but maybe it will help. Good luck with your repair.

Posted on Jul 11, 2010


James Dodson

  • 99 Answers

SOURCE: When using my new Serfas

Do you have the connection to the tire valve tight? You must have the connector pushed completely down and the locking lever pushed in the down position. Be sure it can not be pulled off of the valve while pumping up the tire.

Posted on Feb 12, 2011


Daniel wettstein

  • 69 Answers

SOURCE: my clutch goes straight to the floor with no resistance

What year make model are we talking about

Posted on Mar 03, 2013

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I just have a hard time figuring out how to inflate my tires with this pump. I assume I should use the smaller connection. Can't make it inflate.

I am disappointed to find that the Serfas website has NO instructions for their pumps or other products, as if it is intuitive for a novice to operate them.

As a customer you should contact them and complain.


[email protected]

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