Starting after been stood for a few days.

[davidj]

Hi,

I have had the same problems with several cars I have owned which are fitted with Delorto or Weber Carbs. If the car has been stood for more than a couple of days, the petrol evaporates from the float chambers and to start the car the engine has to be turned over for a significant time, putting load on the starter and usually flattening the battery. Quite often I end up flooding the carbs which makes it even harder to start the car!

Recently I have resorted to taking the tops of the float chambers and pouring petrol in directly; the car starts straight away but it is not a particularly practical solution.

I know I could invest in a electric fuel pump but the mechanical pump works fine once primed, so I don't wish to change. I was wondering if any other solutions had been successfully tried to fix this very annoying problem.

David

[rgh0]

Some owners have installed a priming bulb ( as used for outboard motors) in the fuel line to enable them to hand pump the fuel into the carbs before cranking the engine over.

You will find the posts if you can guess the right search terms to use!

Personally I am an electric fuel pump convert

cheers
Rohan

[bast0n]

Mine starts after about three or four churns after being left for up to 6 weeks in winter so I suggest you look elsewhere for the problem. I have never come across fuel evaporating from Weber Carburettors - well not in my car certainly - and I NEVER use the choke.

This has been discussed at length elsewhere. A properly set up engine WILL start.

Good luck - it is infuriating when the blasted things won't start!

[nebogipfel]

I have never come across fuel evaporating from Weber Carburettors

Ditto,

Evaporation would be very slow from a closed container.

I'd suggest it's leaking out.

You certainly shouldn't need to resort to hand priming or electric pumps

[rgh0]

...... I have never come across fuel evaporating from Weber Carburettors - well not in my car certainly.......

The fuel will certainly evaporate out of the carbs in a relatively short time, especially the more volatile components that are important to get the engine to fire when first cranked over cold. An engine that is in tip top condition will withstand this loss of fuel compoents somewhat better than an engine in average condition but after some time of storage without running, starting will require signficant cranking to fill the carb with fresh fuel with the mechanical pump before it will fire.

How fast this evaporation occurs depends on a range of factors such had ambient temperature and the local fuel fornulation.

cheers
Rohan

[rgh0]

I have never come across fuel evaporating from Weber Carburettors

Ditto,

Evaporation would be very slow from a closed container.

The Weber float bowls are a long way from being a closed container - have a look at the 15 mm diameter hole in the front face of the carbs.

cheers
Rohan

[prezoom]

With ethanol enhanced fuels, the process is speeded up even more. It doesn't seem to make much difference if it is a Weber, or SU. The fuel just goes away. Especially in warmer climates. I am with Rohan on the electric pump. The pump can be a stand alone unit or an auxiliary to the mechanical pump. Flip a switch and wait for the pump to slow down. Instant start. If it is an auxiliary pump, just turn it off. No crawling around, all done from the driver's seat. No long term grinding of the starter.

Rob Walker
26-4889

[bast0n]

I hear what you of the evaporation brigade are saying, but mine has sat in Italy for over a week in temperatures of 35 plus during the day and started with no excessive churning as though it was at home in deep damp Somerset.

Looking at the exploded view of a Weber I just do not see where the evaporation takes place.................it looks to me like a bowl of fuel with a sealed top - doesn't it?

[jk952]

I believe there is a vent, convoluted path maybe, to the hole you see on the air cleaner side .....however my similar vintage lawn mower runs fine on well over a year old gas, though not maybe relevant ...
I found when I increased the level in the bowls (on the elan) and verified both up and down movement of the float mine started much better (as someone said back to basics).
... low fluid level but maybe not from evaporation??
(my floats are a newer shape so hard to interpret the book settings as measurment point vague, so went by fluid level in bowl through a couple of trials)
.02 worth only...

jk

[Galwaylotus]

Hi,

I have had the same problems with several cars I have owned which are fitted with Delorto or Weber Carbs. If the car has been stood for more than a couple of days, the petrol evaporates from the float chambers and to start the car the engine has to be turned over for a significant time, putting load on the starter and usually flattening the battery. Quite often I end up flooding the carbs which makes it even harder to start the car!

My S3 SE was sitting for a couple of months. Before trying to start it last weekend, I took the covers off to check float level adjustment (8.5mm & 15mm) per Miles Wilkins and John Passini books. I reinstalled the covers, turned on my ignition, waited for the electric pump to slow, and pumped the accelerator seven or eight full strokes. Fired and ran in a few seconds. It works for me!

[Allison]

David,

Hi, we have two Elans - and they react differently! One starts fairly happily though the other engine should be in better condition! The other needs a lot of cranking if its been sitting. I blame the valves in the mechanical fuel pump - both cars have mechanical pumps only and I assume that one set are less good than the other.

Peter

[nebogipfel]

I have read the evaporation theory many times and yet it makes no sense. I live in average daytime temperatures at pretty much the same atmospheric pressure as everybody else and I can leave my car a month and it will still start OK. Evaporation would take ages to empty the float bowls, the petrol would probably go stale before it evaporated.

Even if there was a small amount of evaporative loss a couple of engine rotations would fill the carbs again. Have you ever disconnected the fuel delivery pipes to the engine and then hit the starter? .............petrol gushes out.

FWIW I would venture to suggest that if a reasonably regularly used Weber twinc will not start with a 2 or 3 pumps on the go pedal and a few rotations of the engine there is another problem .....unless it's one of the odd ones which seems to insist on a bit of choke, in which case use it.


EDIT: Going back to the original question, have you tried using the choke David?

[fatboyoz]

David,
I believe the answer is two pronged. This is what happens with my Elan.
After being allowed to sit for a day the fuel disappears from the glass bowl of the mechanical fuel pump. As Peter says, this seems to be due to the valves in the pump allowing fuel to flow back into the, lower situated, fuel tank. The car will still start OK though because there is still fuel in the webers.
Allowed to sit for a few more days and the fuel evaporates from the webers as well. Trying to start then requires the engine driven fuel pump to suck fuel from the tank, and then fill the carbs before it will fire. Some amount of starter motor use is required for this.
I got around this problem by fitting, as Rohan has mentioned, a squeeze type, priming pump from an outboard motor under the boot floor. I have purchased an electric, inline pump to replace the squeeze pump as I am quickly getting sick of emptying the boot, removing carpet, foam insulation and wooden boot floor each time I want to prime the engine.
The correct fix would be to have the EDFP overhauled so that the valves do not allow the fuel to drain back into the fuel tank. Perhaps a separate one-way check valve would help in the interim.
Regards,
Colin.

[Robbie693]

.....unless it's one of the odd ones which seems to insist on a bit of choke, in which case use it.

Both of mine have been funny ones

Robbie

[davidj]

Hi,

Thanks for all the posts! I have this problem on two different cars, one with webers and one with delortos. I am in the UK so it is not that warm, but I can guarantee if the cars have been stood for a week they will not start, and if I lift off the carb covers the float chambers will be empty. Other "old" cars I have had in the past with SU's do not exhibit the same problem. Once there is petrol in the float chambers, both cars start instantaneously, warm or cold.

I think Colin has identified the cause of the problem, and as I said in my original post, it could be fixed with a electric pump, but if possible I would like to stick with the manual one.

The squeeze type pumps do sound interesting and a good idea which did not occur to me. Is this what you mean?

http://www.ebay.co.uk/itm/8mm-Fuel-Prim ... 53edf45f2e

My only concern is if it is mounted in the fuel line it would increase the volume of petrol in the line. Would this cause a problem to the pump? I guess not. I guess it should be fitted between the pump and the tank, not between the pump and the carbs?

Cheers,

David