Eng Fuel Filters Man CR900

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

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.

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.

Are you certain they are fuel pumps and not oil pumps? Just double checking

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?

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

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.

Skip.
Get a couple more suggestions?

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.

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.......

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.

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?

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.

Yes I think this happened and am not use the original filters could that be the reason