Click for Cheoy Lee Click for Walker Click for Nordhavn Click for Cross Click for Lurssen

Eng Fuel Filters Man CR900

Discussion in 'Engines' started by CSkipR, Mar 18, 2012.

You need to be registered and signed in to view this content.
  1. CSkipR

    CSkipR Member

    Joined:
    Aug 16, 2008
    Messages:
    947
    Location:
    New Smyrna Beach, Fl
    Going to change the engine fuel filters. Do you change the cannister fuel filter first and then the two filters on top of the engine. Any potential concerns changing the filters I should be aware of. Once changed how do you reprime the engine fuel system. Last time I changed them the mechanic was there.
    Thanks, skip
  2. Beau

    Beau Senior Member

    Joined:
    Jan 15, 2010
    Messages:
    2,180
    Location:
    Cold Spring Harbor, NY
    I have the older 820 s. I usually change my racors, and my spin ons first, filling them with clean diesel thru a filter cloth, then the little screen filter on the primer pump There is a pump/plunger that I unscrew to open and then prime the System. Don't know if this helps you on your engines, though
  3. Capt J

    Capt J Senior Member

    Joined:
    Jul 11, 2005
    Messages:
    12,926
    Location:
    Fort Lauderdale
    Either way, change the racors first then secondaries, vice-versa......On the 820's, sometimes you have to have 1 of the 2 filters off first in order to get the second one off and back on.....Anyways, put a little oil on the gaskets, pre-fill the filters most of the way, then on top of the housing there are 1 or 2 bleed bolts you open then pump the manual pump until solid fuel comes out (don't forget to open your main fuel valves first), then tighten the bleed bolts......have a diapher under the canister filters, and another for bleeding.
  4. Sea Gull

    Sea Gull Member

    Joined:
    Aug 3, 2010
    Messages:
    132
    Location:
    CT
    I do the secondaries on top last.

    When you do the secondaries on top of the engine, be sure to drain all fuel out of them first. This can be a real pain as the drain valves are hard to reach. With the drains open, take the old filters out and clean the housing with brake cleaner. Do not wipe with a rag that might get lint into the housing. Replace the filters after the brake cleaner is dry. Close the drains. Done.

    For the on engine primaries just be sure not to damage the clear plastic bowl at the bottom. You might be able to prefill these with fuel, but I do not.

    The manual priming pump is a pain to use and gives quite a workout by the time you get fuel into the filters. Just keep pumping until you feel resistance and then keep going until it's very hard to pump. you may still have to crank the engines more than once and advance the throttle to get the lines full. You may hear a high pitched whine if there is still air in the system.
  5. CSkipR

    CSkipR Member

    Joined:
    Aug 16, 2008
    Messages:
    947
    Location:
    New Smyrna Beach, Fl
    Electric Fuel Pump

    Okay just realized I have two reverso electric fuel pumps by the front of each engine. Never used these before. Assume I just flip the breaker, turn the valve handle and hit the toggle switch and it will pump fuel to the filters, etc. Does it have to be bleed with this system or does it do that automatically?
  6. Beau

    Beau Senior Member

    Joined:
    Jan 15, 2010
    Messages:
    2,180
    Location:
    Cold Spring Harbor, NY
    Are you certain they are fuel pumps and not oil pumps? Just double checking
  7. CSkipR

    CSkipR Member

    Joined:
    Aug 16, 2008
    Messages:
    947
    Location:
    New Smyrna Beach, Fl
    Absolutely.
  8. Beau

    Beau Senior Member

    Joined:
    Jan 15, 2010
    Messages:
    2,180
    Location:
    Cold Spring Harbor, NY
    OK. Maybe someone with a common rail MAN will join the conversation. I have a service guide for my 820's that is very helpful in detailing all sorts of maintenance and repair. Do you have one for your engines?
  9. CSkipR

    CSkipR Member

    Joined:
    Aug 16, 2008
    Messages:
    947
    Location:
    New Smyrna Beach, Fl
    Yes I have a Man service manual but it does not have the reverso fuel instructions in it. It seems easy enough to operate just not sure about whether I have to remove air manually or not with this system.
  10. Beau

    Beau Senior Member

    Joined:
    Jan 15, 2010
    Messages:
    2,180
    Location:
    Cold Spring Harbor, NY
    If there is a bleed screw between the pump and the engine, I'd open it. But, again, I don 't have the same engines
  11. Freespool

    Freespool New Member

    Joined:
    Aug 27, 2011
    Messages:
    18
    Location:
    Kemah, Texas
    Just turn the handle 90 degrees and hit the button. Lay on it until you hear it squeal. Do it again and again. The CR MAN has anternal air bleed and will push it out on its own. May have to prime some when you try to start as well.
  12. Beau

    Beau Senior Member

    Joined:
    Jan 15, 2010
    Messages:
    2,180
    Location:
    Cold Spring Harbor, NY
    Skip.
    Get a couple more suggestions?
  13. captjohn22

    captjohn22 Member

    Joined:
    Jan 29, 2012
    Messages:
    37
    Location:
    Beach Haven, NJ
    apples and oranges?

    I run a boat with MAN 800CR's. I believe my filter arrangement is different from yours.
    I have a Racor priming pump on the 30 micron Primary filter then the 10 micron MANN-Hummel, then there is one 2 micron filter on which I leave the drain valve open [ there is a drain tube attached that I run to a gallon jug ] when I activate the pump. This fills the filters quickly. When I have a good non aireated flow I close the drain and continuing pumping until the sound indicates the air is out. This has proved to be the quickest and easyest way to get the air out.
    I only drain enough fuel from the Racor to remove the filter since the priming pump must remain submerged in order to work properly. The other two filters are installed dry.
    Do not pour fuel into the 2 micron filter as it may introduce foreign material intio the down stream side.
  14. Capt J

    Capt J Senior Member

    Joined:
    Jul 11, 2005
    Messages:
    12,926
    Location:
    Fort Lauderdale
    Changing fuel filters isn't brain science and neither is getting the air out. I pre-fill the filters most of the way, put them on, change the racor filter, I've even taken the bleed bolt out and filled it with fuel with a lower unit hand pump, put the bleed screw back in and roll the motor over, it'll usually start within the 10th revolution and run........ or just get the filters near full, put them on, open the valve and run the priming pump (with the bleed screw closed) until it changes tone (about 10 mins or less usually), start engine.......
  15. CSkipR

    CSkipR Member

    Joined:
    Aug 16, 2008
    Messages:
    947
    Location:
    New Smyrna Beach, Fl
    Capt John,
    Thanks for the feedback. Yes similar mine is 8cyl and I believe yours is 6. I have two racor filters and 1- primary Man filter and 2- secondary Man filters. Actually I just got info from a Man mechanic about an hour before your post. Here is what he said which is similar to your post. Thanks again, Skip
    After you have drained the filters and changed them, you may prime the system just by using the reverso pump. You do not need to open any bleed valves. Simply prime with the reverso pump for 30 seconds at a time for 3 or 4 times, start the engines you will hear a whining noise coming from the engines that is from the air in the system that will self bleed out. That is all you have to do.
  16. captjohn22

    captjohn22 Member

    Joined:
    Jan 29, 2012
    Messages:
    37
    Location:
    Beach Haven, NJ
    Yes mine are 6 cyl.
    I think air is more of a problem with common rail engines because of the higher pressures in the fuel system.
    My personal boat has cat 3208's. Like most older engines if they get air bound you can crack the fuel fittings where the lines go into the injectors, then crank the engine until fuel runs out of the tubing. Re-tighten them and start the engine.
    This should NEVER be done with common rail engines because the pressure in these lines is much higher and can cause serious injury.
  17. Nicol

    Nicol New Member

    Joined:
    Oct 18, 2015
    Messages:
    32
    Location:
    Seychelles
    I have a man cr 900 I need to prime when the engine is cold after it's hot I don't need to . Anyone know why?
  18. captjohn22

    captjohn22 Member

    Joined:
    Jan 29, 2012
    Messages:
    37
    Location:
    Beach Haven, NJ
    It sounds like you have a fuel leak that is introducing air in to the system. Check the Mann-Hummel filter at the water probe and all O-rings on the filters.
  19. CSkipR

    CSkipR Member

    Joined:
    Aug 16, 2008
    Messages:
    947
    Location:
    New Smyrna Beach, Fl
    Agree air in system likely your issue. Also check your racor and make sure there is no leak. Did this happen to start after changing your racors or Mann fuel filters?
  20. Nicol

    Nicol New Member

    Joined:
    Oct 18, 2015
    Messages:
    32
    Location:
    Seychelles
    Yes I think this happened and am not use the original filters could that be the reason