5 replies to this topic

[Avtovaz]

doing the mini van, its a 1981 car, when its left for ages the fuel drains back to tank, fuel line is empty, also, there is fuel in the tank, i dipped it, but i took the pipe off the carb and sucked and it wont come threw. Its a new stainless fuel pipe to the tank, is there inside of the tank a pipe or something that could have come off? Its been off the road for a long time, but i have had it running fine, just seems strange it drains back to tank.

[phillrulz]

Just a guess, is the tank breather okay? 

[Avtovaz]

never even thought to check!! but i think the fuel cap isnt that good, but will check it thanks!

[sledgehammer]

could be fuel pump valves old , or been affected by the ethanol in the petrol , letting fuel back down the fuel line

 

I had to replace a NOS pump because the valves went like chewing gum - a SU manual pump , the pump had never been on the road

 

and as above fuel vent blocked - sometimes a small hole in the filler cap sometimes a pipe collapsed

 

it is surprising how much vac the pump can create when vent is blocked

Edited by sledgehammer, 19 November 2017 - 08:35 PM.

[phillrulz]

As sledgehammer said, my breather idea is working on the idea, the fuel pump can suck it from the tank, if the breather is blocked it makes a vacuum, when the engine is turned off air bleeds back in through the carb and pushes the fuel back into the tank

[cal844]

When we re engined my estate we had to backfill the line from the carb to pump then pump to carb, took about a week to do the engine, new mechanical pump too!