Dk35 Fuel pump

[Myk]

I have'nt got a manual for my DK35 05 model, so I'm just wondering what the tap near the fuel pump is for.
2 photos below

 

[nixon]

Looks to Me like the fuel bleed port .

 

[Myk]

It turns about 6 full turns in/out or open/shut.

 

[nixon]

I'd say that then it's definitely the bleed port .