MD6A fuel feed puzzle

[Vega1447]

Hi all.
Any comments on the following minor mystery?

I had been away for 3 weeks (sailing round Ireland on a bigger boat).

When I went out to my Vega on return starting battery was low (11.5V) so
I hand cranked the engine a few times de-compressed, then dropped the
decompression lever down and pressed the starter button. The flywheel
turned but no compression - so no fuel getting to injectors.

Cursed a bit and prepared to bleed the system. Decided to give it one
more try with starter - engine fired, all well. Ran perfectly since then.

Not a big deal but puzzling.

How could an airlock develop when boat is unattended and how did it
clear itself by cranking without bleeding?

My theory - the weather had been hot - could the diesel in the injector
feed pipe have expanded creating an airlock at the injectors?

Better theories welcome.

Is this a common phenomenon?

Thanks,

John

V1447 Breakaway

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[stevebirch2002]

Hi John

Can easily be an airlock caused by leak-back. There is a fix for this in the VAGB TEchnical Notes, entails making a small resevoir with 22mm copper pipe.

The no compression seems worrying? Is this lack of compression in teh cylinders? This can be caused after using the decompression lever breaking inside the rocker-box cover. The new rocker box gaskets are much thinner so you need to use two of tehm if you change it.

Sounds as though turning it over sorted the stuff, well done.

Steve B

 

[Vega1447]

Hi Steve,
where can I find the VAGB TEchnical Notes?
Leak-back airlock sounds likely alright - if I knew what it meant! When I said no compression I meant engine didnt fire - sorry for confusion.

Thanks as always,

John

Steve Birch wrote: