Tech Wiki

How to Change Your Racor Filter

Step-by-step directions

In this description the author has the secondary and primary filters backwards. We consider the primary to be the Racor, underneath the head sink in Mark I boats, and the secondary to be th e engine mounted spin on filter. This procedure was copied from older FAQ pages of the website. For a more recent Filter discussion, see this topic on the Message Board, which links right back here!,1124.0.html

  1. Close fuel shut off valve.
  2. Slightly loosen Racor secondary filter.
  3. Using a 1 pound coffee can, insert / hold the coffee can over the filter and finish removing filter.
  4. Remove the filter from the boat and discard. (no draining required, etc.)
  5. Insert new Racor filter in coffee can and fill with clean fuel. [Or, instead, consider filing with an injector cleaner, such as PS Diesel Additive.]
  6. Install new Racor filter (Full).
  7. Slightly loosen primary engine filter.
  8. Using a one gallon zip lock bag under / around the engine filter and remove.
  9. Remove the filter from the boat and discard.
  10. Install new engine filter (Empty – You don’t want to introduce any contaminates at this filter).
  11. Open fuel shut off valve.
  12. Open fuel bleed valve.
  13. Turn on ignition / key.
  14. Wait for very fast fuel pump ticking to become fast.
  15. Close fuel bleed valve.
  16. Fuel Pump ticking should return to normal.
  17. Start engine and check for leaks.


  • As a reminder, you should never have to loosen your injectors to bleed the engine. Only two things: the knurled knob and the nut of the top of the secondary fuel filter bracket.
  • It's so simple to fill the Racor bowl with fuel or fuel additive/injector cleaner. Then open and close the bleed valve a few times and start the engine. That insures that the absolute minimum of air is introduced into the fuel system. Why let air into the system so you have to bleed it out? BTW, using an injector cleaner full-strength works as a injector power wash. Being an oil base it's not harmful to the injectors and is rapidly diluted by the fuel pump mixing in diesel.

Racor filter size model numbers

RACOR FUEL FILTER NUMBERS (from the Racor 220/225R Spin-on Series Manual):

  • R24S 220R, 2 micron replacement element
  • R24T 220R, 10 micron replacement element
  • R24P 220R, 30 mciron
  • R26S 225R, 2 micron
  • R26T 225R, 10 micron
  • R26P 225R, 30 micron


  • S: 2 micron
  • T: 10 micron
  • P: 30 micron