question Air leaking from fuel injector - Zetor 5511

Hi I was wondering if anyone could help me I bought a zetor 5511 last year and it was running fine until now . I am new to all this so dont really no what Im talking about And thought I would get a better opinion .we think the air is coming from the air intake screw last month we changed the screw and washer and it ran fine . every time we use the tractor now you have to bleed the hole system as air is in the fuel . the tractor is loosing power and cutting out as you do things like mowing and its getting dangerous on hills etc does anyone have any information on how I would fix this problem cheers dan

Hi
Start by cheking fuellines and the copperrings on the banjobolts, ushualy hvere air leaks inn fuel leaks out so chek for damp spots.
Bjarne

Bjarne is right but from my experiance air can be sucked in even if no diesel is leaking out. The glas bowle is critical and very hard to get tight. Do you se an airbubble in the bowle is it an indication that air is sucked in. From the symtome description I bet it is an air problem. Even the top hoses from the injectors back to the pump can give you problem if air is leaking into the system.
Lots of redings in this forum in this subject.
Hazze