Bleeding 6BTA

[Richard OFerrall]

I recently changed the fuel cooler fuel lines and separator and engine fuel filters on my Cummins 6BTA 5.9 (330hp). On my old Yanmar, all I had to do after this kind of work was activate the lift pump on the filter assembly and keep pumping until the pump went hard to ensure the system was bled properly.
I tried this using the lift pump built in to the fuel system adjacent to the fuel pump on the Cummins 6BTA, but after a couple hundred strokes and listening to fuel flowing through the pump, the lift pump still hasn’t gone hard.
I don’t use a bleeding bulb or other add-ons, just the built-in lift pump on the engine.
Should I keep pumping, or will the Cummins system not go hard regardless?
Will this suffice after a couple of hundred strokes?
Thanks in advance for any advice…

Topic

[Woo]

Might see or hear you out there mate. We usually fish the ‘shelf off Cape Moreton. Can’t wait to get stuck into them and hopefully get a run at Fraser this year too!

All the best, Ben

[Richard OFerrall]

Thanks Woo… the answers I’ve received to this query have been extremely helpful, and yours was confirmation that I haven’t totally screwed up, and that what I’ve done should be fine.

The blues are the target starting next week through to May! Hopefully, it will be a good season.

Many thanks to all respondents.

[Woo]

Rick, I personally don’t pre-fill the filter as I want to ensure every bit of fuel is filtered.

It’s not overly onerous to use the hand lift pump to draw fuel through, and by the time you hear the squeak, it will be ready to fire. Full throttle to wind it over, and reduce throttle when it fires. Give it a few minutes run time before casting off. I actually like to stop the engine, wait a few minutes, and double check it will re-fire at idle speed, just to be certain.

I’ve never felt the need to crack any lines. My old spec 210B’s were a different story, but we’re not lumped with that lift pump on your engine.

Good luck with the season, keen to get amongst the Blues myself 🙂

[Richard OFerrall]

Thanks Julian… it didn’t really get much stiffer, but it did start to squeak quite noticeably. I was probably being lazy and just went ahead and changed the low pressure fuel lines and filters without fully consulting the manual, (wrongly) assuming that the built in pump was going to be the solution to all bleeding as is was on the Yanmar.
I didn’t top the fuel filter off either, just assumed it would fill using the lift pump – again, reverting to what worked with the Yanmar, but also being lazy and fed up with being covered in diesel.
I haven’t run the engine yet, as it’s early morning in Australia, and I wanted to get some feedback before I gave it a shot, but will go and do so shortly and get back to you.
Meanwhile, many thanks to you and the other respondents, and I promise you all not to be so lazy next time, and will follow the procedure in the engine manual in full when I do the same to the other engine.
As usual, there are two ways to do things, the correct way, and the other way… but in my defence, I’ve just spent an entire winter getting this rather tired and poorly maintained boat back up to top shape for the start of the game fishing season here in Queensland, and was admittedly just getting sloppy after three months bent up like a pretzel in the engine room and other spaces…

[Julian]

And make sure you top the fuel filter off as much as possible. I get it in position under the housing. Fill it to the top with a cup and then put it on. It will fire right over with just a few pumps.

[Julian]

Yes it will get stiff and squeak. It shouldnt take more than a few pumps.

Try to start it and with some throttle. Back it off as soon as it fires. Run it for a bit before you leave your slip.

If it dies, loosen all 6 injectors 1/2 a turn, crank for a few seconds, retighten, pump, and try again.

[Richard OFerrall]

Yes…! It would have been 50+ pumping strokes, and then it did exactly that… it started to “squeak”. Is that a good indication that it’s bled all the air out and is ready to run?

[Francis Valerio]

Did you fill the filters with fuel? If not, remove them and fill them.

Then you can loosen the fuel line that goes to the fuel pump (IP…P7100 I think you have)) (not the lift pump).

Now you can try pumping the lift pump to see if fuel is coming out of that loose fitting. If or when it does then you can tighten it up and loosen a few injector nuts to see if you have any magic happening.

I am not familiar with your particular IP but I would try that and see what happens.

[ablicpa]

Kick the engines over 1/2 crank. Lift pump is cam driven, it might have stopped on a low point on the cam.

I had a 6BT 210hp & there was a bleed fitting on the high pressure pump that had to be cracked open to get it to bleed air out. If you have the engine maintenance manual it will tell you how to bleed. Did you fill the filter with diesel before re-install?

[Rob Schepis]

After a bunch of pumps did you hear it “squeak” ?

[Author]

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