When to “fully” bleed/vent fuel lines + crank no-start

rreegg

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Hey all, have a question about when and under what conditions to “fully” bleed the fuel lines.

The engine is a Volvo marine 2 cyl diesel, MD6B. Dealing with a crank but no start issue after not running the engine for about 6 months.

I’ve cracked open the fuel lines at both injectors and get fuel when cranking - is this sufficient to determine the fuel lines do not need to be bled?

Have the engine manual and there is further bleeding procedure mentioned but not sure if it’s relevant since the injectors are getting at least some fuel.

asking because the “full” bleeding procedure is somewhat involved, needing a hand pump (which I don’t have), and the vent screw on the fuel filter housing is pretty buggered up.

Haven’t had issues with this engine before and have replaced the fuel filter and removed the injectors previously without needing to do extensive fuel line bleeding - it would start by cranking.

Any advice or tips are appreciated. My next steps are to look for leaks/air intrusion on the fuel supply/return lines and try to do more bleeding.
 

ut99dot1

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hi, once you get it running it should bleed it self automatically. You might need to do a lot of cranking to get the fuel where it's supposed to be, because the starter got to work the injection pump AND the compression. I always use an electrical lift pump, makes the entire procedure alot easier. Check if glowplugs work, should make things easier.

Also run a clear fuel line to the injection pump, so you can see if there's bubbles going in
 

rreegg

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Think the issue has to do with either old batteries or a starter that's going out. Haven't had the time to swap out the batteries yet but the cranks have gotten really slow - not much to indicate there's fuel delivery problems at this point
 

DaveBen

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The engine needs to crank at 500 rpm or more before it will start. Batteries are the number one cause of no start.
 

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