Fuel Starvation?? Cutting out at Speed- Help! Help me to Keep my Beloved Car

I have a daily driver 1800 auto clipper which is fitted with a weber carb of some sort…

It starts great from cold, and without tempting fate, runs great. Starting from hot if the car has been left for say 15 minutes or more is another matter. if I don't get the issue sorted, my better half who refuses to drive it until its fixed and is therefore wanting me to sell (we have a one year old daughter and with some justification doesn't want to get stranded out with her in the winter rain).

 I have worked out that the carb is flooding when the car is parked.

The fuel return line from the brand new fuel separator bowl is blanked off and when the car is parked, the pressure in the fuel system is causing the carb to flood. I reconnected the return line and the hot starting issue was instantly sorted. Result! No more flooding. But… at speed, the car cut out due to no fuel. I put a restrictor (looks like a carburettor jet) which I ordered from Webcon fuel systems in the return line and a test drive suggested all was well.

Success was short lived however because soon after joining the motorway this morning, it cut out again. Blanking the return from the fuel separator bowl meant that the car then ran perfectly well for the rest of the journey. But I know that starting from hot will be an issue again…

I find it really bizarre that the fuel is finding it easier to (I assume) head along a restricted return line as opposed to taking what I would imagine is a much easier route to the carburettor.

Am I barking up the wrong tree? Any ideas / solutions that you have will be greatly appreciated - I don't want to have to sell what is otherwise a great car but by the same token cant risk the missus and my daughter getting stuck…

Your help will be hugely appreciated.

might be carb icing issues, make sure the carb heater is fitted to the weber adaptor and look at the airbox:
http://www.clubgti.com/showthread.php?144497

Thanks for your reply but I don't think its that - its been like it all summer!

The car is difficult to start because the carb is flooding. having tried restricting the return line, although this cured the hot start problem, a more serious one resulted because the car would simply run out of fuel at speed - petrol was being pumped back down the return line as opposed to going to the carb!

Unless anyone has any other - very welcome - suggestions, I can only conclude that the carb floats aren't set right and / or the valves in the carb are worn.

yeah I mean for the problem after you fixed the fuel return

it doesnt necessarily have to be that cold out for carb icing to strike either. best to check the warm air and carb heating system while you're under the bonnet for sure.

is the rubber flange under the carb adaptor ok? often split especially if the steady bracket from the front of the airbox to the cylinder head is missing as the carb will flop all over he place

but yeah, may want to budget for a full carb rebuild kit too, split it down and check everythign

thanks again - funnily enough, the rubber mount was the first thing I checked about a year ago - it was fine. I've put up with it since as I can always coax it into life but the missus is understandably not so keen to do so, especially with my little 'un on board…

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RichieS in the usergroup 'Regular'






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  Just thought I'd give an update to this issue, which, without wanting to tempt fate, I seem to have sorted by fitting a new fuel reservoir / vapour separator. Quite why this has made a difference I don't know but it has.
The return line from this is still blanked off (as I believe is recommended for Weber carbs) and having taken the old one apart, it appears to be little more than a small pot for fuel to sit in.

However, since fitting, the car just needs a small throttle opening and she starts up just fine…

the return is blocked off if you have starvation issues due to the fuel restrictor being missing from the return port on the swirl pot, if it has this then you could try plumbing it all back to factory then see how you go

thanks mate but with the new pot and the return line connected, it would cut out at speed, just as the old one did. But with the return line blanked off on the old pot, it would be a swine to start from hot if the car had been left a while - clearly the car was flooding. the new pot, though the return is still blanked off, does not suffer the same…weird but I'm happy that the car is now much easier to start…

long may it continue