Intermittent stalling; won't re-start

[Ian and Lins]

This is driving me nuts.
The van usually starts and run very well but occasionally the van will start, then appear to run out of fuel and stop. Plenty of fuel in the tank. It seems to be a more prevalent problem when the van has been run for a few miles, parked for a short while then re-started.
I suspected the fuel pump (and so did a Green Flag mechanic) as when you manually pushed the fuel lever, petrol would not be pumped through. Even 'though the pump was new only a couple of years ago, I replaced it, along with the push rod a couple of days ago. This SEEMED to fix the problem as the van started immediately, ran well and then re-started on various attempts during the day.
Yesterday the problem returned. I'm thinking fuel line and/or petrol tank but; any ideas people?

[itchyfeet]

Go back and check the pump as you did before by manually moving the lever, new pumps can be faulty too.
Measure your pushrod movement, IIRC its 4mm from flush, better than measuring the length as the drive shaft can be fitted with incorrect washers affecting it.
Then I'd recheck the tiny conical filter on carb inlet.

Could also be a tiny pin hole on fuel pipe, draws in air rather than fuel but not big enough to leak (fuel is under negative pressure), when hot this hole could be getting bigger, try changing the rubber fuel pipe in the engine bay.

[CovKid]

I'm with Itchyfeet on the pinhole leak and it can be anywhere. The only solution I found was to go electric because:

a) You quickly find the source of any leak as its now under pressure between pump and carb
b) The line and carb is instantly primed.

The drawbacks:

a) An old/weak carb float valve can cause engine to flood rather than be starved of fuel.
b) fuel line has to be good quality and secure.

Manual pump problems can be difficult to diagnose as the volume of fuel moved is directly related to engine speed and you can't always see whats going on. Any air leak between pump and tank will cause the fuel to run back after standing, emptying the line. It'll start on whats in float bowl then conk out 30 secs later.

[Ian and Lins]

Thanks Itchyfeet and CovKid. We took the new pump off last night and did the 'push with a finger on the lever' test and cannot get any fuel pumped through. Certainly looks like the new pump has failed. Going through the fuel pipes and replacing them. The electric fule pump option is beckoning.
Thanks again.

[Ian and Lins]

Yep, put a known good pump on, replaced fuel lines and it starts and runs. Brand new fuel pump; I should not have assumed it couldn't be that.

Thanks again Itchey Feet and CovKid

[itchyfeet]

You are welcome.
If you changed the pump and the lines together then are you sure you know which was the problem?

[Ian and Lins]

Not exacly sure; changed the lines 'cause I didn't know how old they were so it was a cheap precautionary thing to do and it would eliminate them as a potential problem area. I did try the new pump off the van as per the Haynes method and no matter which way around I put the pipes into the fuel I couldn't get it to pump fuel. Could have been lines, I think it was the pump or a combination of both were at fault. Running fine now.
Thanks again.