Priming 5.9 QSB After Fuel Filter change

magicbus · Jun 12, 2012

Sorry if this has been covered but search didn't help. When I change out my 2 micron on-engine filter do I let the lift pump refill the filter for a while before starting the engine? Any thoughts on how long? I don't see a bleed point anywhere. Apparently I got lucky last time by dumping the old filter contents to the new one :facepalm:

and don't want to try that again now that I've become a bit more educated about diesels.

Dave

timjet · Jun 12, 2012

I'm not sure, go to boatdiesel.com and find out.
But to be on the safe side, fill the new filter with fresh diesel fuel and you're covered.

jleonard · Jun 12, 2012

There is likely a bleed port on top of the filter houosing. Most engines have this feature. All the older Cummins did for sure, but I haven't spent any time nosing around a QSB.

magicbus · Jun 12, 2012

Ah but the problem with "fresh" fuel is that it has not been cleaned to the required 2 microns, but thanks for the boatdiesel.com tip. I think there is a screw in the top of the filter housing. I will try opening that and run the lift pump. I should have thought of that!

Thanks,
Dave

Anode · Jun 12, 2012

If it's a spin on vertically mounted I just prime with them slightly loose until I see some fuel seep and then tighten.

RickB · Jun 13, 2012

magicbus said:
Ah but the problem with "fresh" fuel is that it has not been cleaned to the required 2 microns ...

For what it's worth, when you drain a cartridge filter, all but a very small amount of what comes out is from the non-filtered side of the element.

If you want to be really fussy about it, install it dry and use the lift pump to fill it, that way all the fuel goes through the element but you are more likely to have carpal tunnel problems than injection system problems.

Scary · Jun 13, 2012

I guess that depends on what kind of lift pump

RickB said:
For what it's worth, when you drain a cartridge filter, all but a very small amount of what comes out is from the non-filtered side of the element.

If you want to be really fussy about it, install it dry and use the lift pump to fill it, that way all the fuel goes through the element but you are more likely to have carpal tunnel problems than injection system problems.

Some pump housing on the Cummins have a priming plunger on the top of the filter mount. I believe that the Cummins is self bleeding so in theory you could just keep cranking. I usually refilled my filter with fresh fuel, but on one occasion I just cranked until the engine started, it took several restarts to clean up and run smooth. But it did bleed it self out. You would want a healthy battery bank.

honeybadger · Jun 13, 2012

On the Yanmar last winter it ran out of fuel due to the primary filter being clogged. It was a on the fly fix i replaced both filters filling them with fresh Diesel first, looked all over for a pump or bleeder, didnt find it, So i had the Captain spin the motor over after i cracked the seal on each injector, foam came out for about 5 seconds then fuel, Stopped tightened the injectors back up the boat fired up ran smooth and we were off in less than 20 mins. This is how we started an old diesel tractor if it ran out of fuel when i was a kid.

Priming 5.9 QSB After Fuel Filter change

magicbus

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timjet

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jleonard

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magicbus

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Anode

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RickB

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Scary

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honeybadger

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