Hot weather fuel problems?

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davecosford

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For the second weekend running we've spluttered to an almost stop. After around 30 minutes of running the bus lost all power under load but still ticks over. After a 5 minute stop to have a look and let the traffic get by its back to normal for another 30 minutes or so.

Both times this has happened after filling up the tank with 'cold' petrol We're back to normal flying along at 50mph.

A few of my thought for discussion.

1. Does the 'cold' petrol stop any vapour lock as the 'hot' petrol from a weekend in the sun has the temperature reduced (it's fine on the drive there after a week in a cold dark garage)

2. Not sure the fuel pipe is routed very well. I've uploaded some photos but it doesn't look great.

3. Maybe I should keep some petrol in the fridge and add it just before I leave. Not sure I'd get enough in the ice cube tray to make a difference 😉

Help please
 

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ozziedog

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I’d start with a little bit of motor maintenance. First thing I’d look at is my valve clearances as that does sound a strong contender. Next I’d look at my points, not so much the gap but are they actually opening and closing. Condenser swap if you have one. Only junk your condenser when you are a hundred per cent sure it was the issue, then you can always re use it as a known good spare. Clean and gap plugs then use a large clear water bottle to check for fuel pump pressure / flow as that does sound a possibility but best to do that with a stone cold motor. The coil is also as mentioned ^^^ another suspect, but start with cold motor stuff like valves and fuel pressure / flow, and plugs before changing tooooo many things. Try your hardest not to get changing stuff Willy nilly so you can actually track exactly what is the ‘ cure ‘ for your motor.

Ozziedog,,,,,,,,keep us in the loop bud :)
 

mike202

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Bit of a mystery that one. I’ve has a couple of instances where on a hot day my engine is running along great and then after a short stop at the petrol station or shop, for say about 20 mins the engine will restart but conks out after about one minute later. Fortunately it hasn’t happened for a couple of years and I changed quite a few ancillaries since then.
I never understood what my problem was so I’m afraid I can’t tell what yours is !
I can’t see anything wrong with your fuel line position. I would check the basics like Ozzie says above but my guess would be something electrical that’s getting too hot rather than a fuel problem.
 

70-CA-Panel

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I had an issue where every hill I went up the engine got hotter and just died, turned out to be the fuel pump rod getting hot and expanding getting stuck in the bake-light sleeve. Replaced this rod with an old one and haven’t had the problem since. Sounds like your engine still idles though where mine completely shut off so not sure how useful this is.
The fuel pipe looks ok, the intake manifold shouldn’t get that hot to bother the pipe.
Is the fuel filter underneath the bus above the gearbox? Have a look to see it’s clean inside too.
 
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davecosford

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So this week's adventure in the bus was going really well. No problems at speed or on the go but now it's decided not to idle....yay


The trip was mainly in central London traffic rather than higher speed motorways. The only thing I've picked up from poking around is the vacuum hose (at least that's what I think it is) isn't tight or connected using any hose clips. Looks a bit tired...

Thoughts on my diagnosis?

The pain in the arse is I've just booked a next week in Dorset (face palm)

I've pinged both of the local recommended garages but I'm guessing I'm out of time.

Help. (Feel free to pop round to Hertford and put me straight)
 

Elibomrod68

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Idle issues are normally just a blocked idle jet, easy to get to on rhs off carb, make sure you don’t short the battery connection on alternator undoing it. Just blow through with carb or brake cleaner.

Unlikely to be the cause of other problems but noticed the vacuum line to dizzy is just a rubber pipe…ought to be solid pipe with loop that sticks up high (still uses two short pieces of rubber to connect) so fuel can’t run down into vacuum can by gravity and ruin the diaphragm. I used a section of brake pipe for my bro in laws still running fine.

I also lifted my fuel pipe off the inlet manifold by cable tying to fan housing…sure I read it somewhere that if gets too hot can get a Vapour block.
 

JohnVW

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I had a similar issue ....mine was tiny speck of dirt on the pilot jet. V easy to remove, it's on r/h side of carb looking from rear. Unscrew it, clean it and screw back in. It needs no adjustment.
 

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