Lotus Elan and Lotus Elan Plus 2 Forums

I have an Elan+2 which is not used often enough!! When left in the garage about a quarter of a tank of fuel disappears every four weeks! The tank has been pressure tested - newspaper under the cat shows no trace of fuel - the inside does not smell of petrol!! Any suggestion on what next to check most welocme!!
Thanks in anticpation -- Chris

Unless you have a teenage son or daughter short of gas for their car it sounds very strange, cant think of any other cause if you cant see or smell the loss !!

A plus 2 tank if full has a fuel level above the carbs and evaporation out of the carbs and replenishment from the tank by gravity could lead to a small loss but a quarter of a tank sounds far to much. My plus 2 does not experience any significant loss in the same circumstances

Rohan

Chris,
Without external loss (leak or smell) it sounds strange, are you sure you fuel gauge
is accurate? maybe after standing for a while the gauge/stabilizer /tank unit is giving problems.
Brian.

It is certainly not the fuel gauge - my wallet tells me the stuff is going somewhere - can it be anything to do with the vent system? By the way the car lives in a garage with several other - which do not suffer fuel loss - so do not think it is an envirmental problem
chris :unsure:

Hello, An environmental problem it may be... I have a 1969 +2 with Strombergs, in Ohio in the USA and must admit to the same problem. I've stored it outside 90% of the time and have parked it with 1/2 to 1/4 of a gallon of gas in it (YES I"M SURE) and then find it is OUT OF GAS a month later without ever having been started. Glad to hear someone else has this demon gas evaporative problem also. I was thinking gnomes. I have no fuel odors or physical drip leakage anywhere...

I have same problem too - fuel definately evaporates - I believe through vents under sills.

Teenage daughters not the problem as they are the main users who complain!! It does seem others have experienced this problem - has anybody fixed it? I believe it is the venting system of the tank and that modern petrol "boils" at somewhere around 45?C. Petrol varies a lot through out the World and the "mix" can be changed up to six times a year - I am in Germany where there is often a quite high methanol content - destroys your feul pump as well!!

Heh, heh the other cars are in the dark of the night sucking your Elan dry. You might have vampire cars

Mike Geiger

I have exactly the same problem, basically I loose a couple of litres a week, often my lotus is completely dry right through to the carbs. In the years that I have noticed this I have come to the following conclusion;
my fuel is evaporating via the breather tubes. But it only becomes a problem when the car is garaged, my garage gets relatively warm in the summer which I believe causes rapid evaporation. I temporarily reduced evaporation by plugging one of the gas expansion tubes out of the tank. But the problem just doesnt seem to be resolved, when I ran the car daily, this simply wasn't a problem...

I have not had the problem to that extent, however when I first had my car I could always smell petrol in the garage. The garage lets wind in under the door and I realised this was blowing through the vent pipes. Being so large, 1 inch in diameter is sufficient for air to blow through. I fixed it by putting corks (wine bottle corks are a nice fit) in both when the car is stored. I forgot to take them out once, it didn't make any difference but I think I got pretty good fuel economy, mind I was only driving gently (running in), not over 3000 or so revs.

Graham
70 +2s

Thaanks for those who pointed me in the direction of the vent tubes. A pity about ssome of the comments that had no added value! As a result of the vaarious suggestions I have plugged one side with 12mm bolt and sealer and done the same on the other - but witha 4mm hole drilled up the bolt. Of course I now cannot completely fill the tank - but so what. Will let you know if it works!

After the best part of a month there has been no fuel loss with the vent pipe "plugged" as described. Thanks to those who pointed me in the right direction,
Chris Draper