Fuel filter change

[John Langford]

Hi Brian,
In your recent post on changing the on-engine fuel filter on your M35B you indicated that you first turned on the pump by turning the key to on (I assume that means turning the key as far as it will go and holding it...is that correct?) and then actually running the engine for a minute before closing the bleed knob. Is the latter necessary to completely purge the air or could you get the fuel to run cleanly without it?

Thanks for the clarification but I get confused about what procedures apply to a M35B as opposed to a M25.

Cheers,
John Langford
Calypso #1431

[reedbr]

Actually, gravity and the fuel shutoff valve in the port cockpit locker did most my work for me.  I skipped some of the detail, but it was my impression that the electric fuel pump worked with the key in the on position, not just the glow plug (spring return) position.

I'll try to be more exact here of my steps:
(1)  Shut off the fuel line in the port cockpit locker under the inspection port.
(2)  Unscrewed the engine fuel filter.
(3)  Wiped up about a 1/2 pint of fuel that came out at the same time.  There was no addition flow with the fuel line cut off.
(4)  Filled the new filter with fresh fuel and screwed it up to the mount lightly.
(5)  Had my daughter open the fuel line valve in the cockpit while I unscrewed the filter slightly.  When fuel began spilling out the top of the filter I tightened it back up (and wiped up my new spill)
(6)  I did not touch any bleeder on the filter mount.  I did loosen the knurled bleeder knob on the same side of the engine 1 full turn.
(7)  Daughter turned the key to the run position (I'm assuming the fuel pump was pumping).  I waited 60 seconds and then closed the bleeder.  Then I backed it off the bleeder a quarter turn and started the engine (actually, she started the engine, it's good training).  
(  Let it run for another minute or two this way and then closed the bleeder completely
(9) Ran it in gear in the slip for 10 minutes and idled for another 10 minutes.

I think leaving the bleeder cracked 1/4 turn open for the first minute allows more fuel to pass, half of which just returns to the tank.  This way if there is any air in the line you should get it out sooner rather than trying to burn everything that is in the line.  The two times I've done my Racor, I haven't touched the engine bleeder.  I'm no expert though.  This brings my grand total of diesel fuel filter changes to three.  But so far (knock on teak) I'm batting 1000.

Let me know if you need any other pictures or info.

subject:  fuel bleed, fuel bleeding

[Saribbean]

I cant locate the bleeder knob on the filter or the knurled bleeder knob.  Can you please post a picture.  Thanks!

[Stu Jackson]

I cant locate the bleeder knob on the filter or the knurled bleeder knob.  Can you please post a picture.  Thanks!

It appears that you have a Mark II (2003 boat).  Your engine is self-bleeding, the knurled knob was for the M25 series engines.

Don't bother with the bleeder knob on the filter, waste of time, let the fuel pump do the work, all of it.

Your engine also should also be wired so that the fuel pump only comes on when the glow plugs are energized OR the oil pressure is made (engine running).  Look in the Critical Upgrades topic for a discussion of this.

[Saribbean]

Stu,
What part of the critical upgrades should I look at pertaining to this post?   Wiring harness? My hull number is 1654, from what I have read I don't need the new harness correct?  Sorry if I seem a little slow, just got the boat.

Thanks

[Stu Jackson]

Critical Upgrades is all of three pages, with pretty good subject headers.

This one:

http://c34.org/bbs/index.php/topic,5078.msg41829.html#msg41829

[Ron Hill]

Sar : Just make sure that your new filter is full of fuel so the least amount of air goes into your M35BC self bleeding fuel system.

Look for the "Critical Updates" that are involved with M35 engine and the MK II hull.

A thought

[Saribbean]

Beauty thanks for your help.!

[kwaltersmi]

FYI - Both the M-25XPB and M-35B are self-priming. Per the manual, here's what Universal says is necessary (but unlikely) for bleeding air: 

If it becomes necessary to bleed air from the on engine fuel
system, tum the panel key ON and intennitently 5- 10 seconds.
Activate the pre-heat circuit. This activates the fuel
pump which draws fuel into the on-engine fuel system and
drives air out via the fuel return.

If high pressure injector lines need to be bled, loosen the
injector line nut at each injector, open the throttle and crank
the engine over until fuel sports from between the nut and
line. Then secure the nuts and start the engine as normal.

To change the fuel filter:
1. Shut fuel supply off.
2. Loosen the fuel filter, turning counterclockwise with a filter
wrench.
3. Using a rag, wipe clean the sealing face on the housing
bracket so the new filter can be seated properly.
4. Lightly oil the sealing O-ring on the new filter. To reinstall,
tum the filter assembly clockwise carefully until the
O-ring contacts the sealing surface of the housing bracket.
Tum 2/3 further with the filter wrench.
5. Turn on the fuel and start the engine. The normal preheat
function should quickly prime the system and the engine
should start.

[Stu Jackson]

If it becomes necessary to bleed air from the on engine fuel
system, tum the panel key ON and intennitently 5- 10 seconds.
Activate the pre-heat circuit. This activates the fuel
pump which draws fuel into the on-engine fuel system and
drives air out via the fuel return.

That's exactly the issue Dave brought up discussed in Critical Upgrades.  Self-bleeding or not, I fail to understand how energizing the glow plugs makes any sense when one is trying to bleed the engine.

I know, I know, I know, that's how they wired them.  Doesn't mean I have to agree with it. 

Detailed earlier discussions are in that Critical Upgrades topic.