Whiffs of petrol?

[gouldsborough7]

Something I meant to ask members about, and keep forgetting until I next get into my Berli: pong of petrol!

My tank does not have the original overflow pipe going to ground from the tank, as I modified it so that the overflow pipe goes back to the neck of the filler. Keeping the pipe bore at its maximum, without any restrictions, allows me to fill the tank at a fast rate. Originally, before the mod, I had to squeeze the petrol in at a snail's pace.

There are no visible leaks, or even stains, in and around the boot area. Yet, if the car has been locked up for a few days, with windows closed, there is just a hint of petrol fumes. Leaving the windows open a few inches (inside my garage)results in no pong!

I did wonder whether my search at the rear end was wrong, and that the fumes were coming through from the engine area. However, there is no obvious problem there as well.

Anybody had this experience, and hopefully sussed out a cure?

Cheers
Mike

[Dane_Rescueman]

Re: Whiffs of petrol?

Hi Mike.

Webers can "breathe" fumes from various parts of their anatomy.
Burton power suggest that armoured flexible fuel pipe can emit fumes through the pipe walls too.

I had a pancake filter on my downdraft Weber. The carb would occasionally cough back through this. Yup it was rather lean on the overrun!

[gouldsborough7]

Re: Whiffs of petrol?

Hi Dane
I did wonder whether the fumes were coming from the carburettor or air-filter direction. My Berli has a 3 litre Grannie carb, which may not be plumbed-in in an environmentally-friendly way!

On reflection, I think the problem became more obvious after I swapped over to my hard-top for the Winter. The soft-top probably had sufficient gaps to cope with the fumes. I know that leaving both windows open just a few inches makes the problem disappear. I'll have to sniff around the engine compartment after my next journey.

Cheers
Mike

[CABRIOBOB]

Re: Whiffs of petrol?

Mike,
I have the same issue with my Roadster to the extent I have just replaced my fuel tank cap and the fuel gauge sender unit and rubber seal even though they were not leaking fuel.
I have repositioned the tank overflow thinking it was leaking when driving hard on bends and even had someone follow me to watch for leaking fuel and nothing leaking as always dry but there is always a wiff of petrol only when driving hard on bends and seems ok driving like a volvo driver. I thought of the carb fumes but the wiff always seems to be coming from the rear of the car, unless it is petrol running out of the exhaust being set up to rich !!!.

[gouldsborough7]

Re: Whiffs of petrol?

Bob
I had this sort of problem on my previous kit - a Robin Hood Exmo (Lotus 7 clone). The stainless steel factory tank was poorly constructed around the sender area. Despite experimenting with gaskets and goo, plus changes to the way the sender was held in place, the inevitable failures came back to the duff design. In the end, I took the plunge and bought a polycarbonate tank, with a better sender fixing, and the problem disappeared!

On my Berli, I cannot see any of the tell-tale signs per my Robin Hood, and having got rid of the rubbish overflow design, there is no trace of any fuel leaking out. Sniffing around all of the obvious places produces no pong. Yet lock the car up for a day or two, and back it comes. While in my garage, I leave the 2 windows down a couple of inches, with no problem. Might be the carb area, I suppose? Will keep looking & sniffing.

Cheers
Mike