Fuel system draws air ?

[logonberry]

Hi, Aussie JCB owner and self mechanic here, I am having trouble keeping my JCB 3CX running. It has a Perkins 4236 engine with Lucas CAV injector pump. I usually have no trouble bleeding the system when I ocasionaly run out of fuel, but this time the machine runs for about a minute and then stalls again. this has happened five times and I am sick of bleeding it. I assume that air is being drawn into the system as there seems to be plenty of fuel to all points in the system. I have dismantled the whole fuel line and filter assembly and have found that the lines have rubber rings/seals on them . they are not O rings. Thing is some of the seals are at the front of the flare and some behind between the nut and the flare. Where should these seals be ? Should the (fuel line ) joint/seal be metal to metal ? I have downloaded a manual but it was of no use whatever ( hard to find, very expensive, particularly as postage to aus around $70) Hope you can help , Cheers, Roy.

 

[AJ.]

Have you checked the brass gauze in the lift pump, if not take the dome top off the pump you will find the gauze filter underneath it, take out the gauze and clean it, clean the pump body, put things back, bleed and try again, about the pipe sealing rings, if you have a juel injection shop at hand get a some new ones.
AJ

 

[logonberry]

thanks AJ, I managed to buy some rubber rings today .Tomorrow cleaning and reassembly. and bleeding