MG MGB and MGB GT Tech Talk
My 1967 B has a very slight gas odor in the cockpit when warmed and driving. I can't find any reference to this by searching the forum. Is this a normal thing or could it be running too rich, have a leak, or what?
I know I have a choke-cable problem so it could be staying partially closed.
Any insight? Thanks!
Lew
how old is your gas tank????? that old then it is time to replace.
Gas tank is original, I think. It doesn't have an odor unless it's running.
I'm interested in the responses to this question, as I, too, notice a Gasoline odor while motor is running. Granted, I think my car is running rich at the moment.. but I also had they same smell with my MGA I owned.
On the older model cars (prior to 70?) the gas tanks are not vented through the vapor canister and charcoal canisters. The gas cap had to have a small (1/16) hole in it. I've found that over time the gas cap's get replaced with the non drilled version. This causes an over pressure build up in the tank (especially in the summer) and usually the weak link is the rubber pipe going through the trunk, starts to leak a little vapor. Had this problem on my 72 after removing and plugging the vent line and not drilling my cap. All gas tanks after 70 (I believe) used the vented line system.
One prime area to look at is the squarish O-ring (called a gland) on the little plastic pipe running between the carburettor bowl and the jet. These things sometimes drip and the smell quickly enters the cockpit. This leak is particularly dangerous since it is near the exhaust manifold.
If you had a later car I would say that it was the evaporative loss system (the hoses in the trunk), but they didn't show up until after 1967 so that can't be the case.
Brian!
You may have just made my day... I have been fighting this problem for some time, replacing bits here and there to try and seal up the tank ('69 GT with fumes from the rear) I will check my gas cap tonight, I'm not sure why I never thought to check that!
Matt
I had this same problem. Check to make sure the charcol cannister is working properly. There is a line that run from the gas tank to the cannister. Make sure that line is not clogged. Also, check all the hoses from the cannister itself to make sure they are in good condition. The hose on the bottom of the cannister that runs down toward the ground is important. Also, you can take the cannister apart and put the charcol out in the sun to recharge it, or go to the pet store and buy fish tank charcol, which is the same, and replace it.
I am pretty sure that John Twist of University Motors has a video on uTube about the charcol cannister.
There is also the vapor cannister in the trunk. I have never heard of the vapor cannister itself being bad, but the hoses that run directly to the gas tank go bad, get old and crack and leak fumes, and cause a smell.
Good luck.
(Now I'm off to check to see if my gas cap is properly vented. Thanks Brian!)
Your '67 has no evaporative loss stuff so never mind that.
You must have a vented gas cap, however so check that... usually the symptom is poor running because sucking fuel from the tank creates a vaccum and then... no more gas to carbs!
Turn on your ignition and check the underside and around the carbs, intake manifold, fuel flex hoses, fuel line fittings and overflow pipes. Any drips mean trouble.
Other easily distinguished symptoms include thin brownish deposits or yellowy deposits, visibly worn fittings or hoses or dampness or areas where dirt appears to be partially "washed" off.
Most likely spots are at the ends of the fuel hoses (they are regular hose covered in abrasion resistant steel mesh) where they like to crack, the bottom of the jet carrier, as stated above and the carb bowl overflow (typically from a sticking or loose needle and seat).
I was driven crazy over my rear carb. The overflow was dribbling. It turned out to be a hole in the float.
Also I had some of the bad needle valves in the carbs.
I also had minor leaks at fuel fittings.
What I did was to disconnect the dizzy. Then I turned the key on to pressurize the hoses to look for leaks.
Larry
If it ends up being the glands at the flaot bowls on the carb, mke sure you get the correct gland to repalce it with, alot of vendor sell a round o-ring, that is not correct and most of times doesn't stop the leak for very long, Joe Curto has the correct gland, it has square edges on it and will come with a brass sealing washer.
<http:www.joecurto.com>
Mad Matt F Wrote:
My 67 B ALWAYS smelled like gas. If it didn't the tank was empty!
But, with a 45 DCOE with velocity stack and a big cam, whenever I stepped on the gas pedal, Gas Vapors literally flew out the vleocity stacks.
so, this was very common for me, remember the carbs are right there under your nose!
Its part of the charm of english sports cars!
its just too bad today's gas just doesn't smell as good as the old stuff with lots of octane!
B