>Date: Tue, 25 Nov 97 19:38:20 EST
>From: robert williford <<RDWILLI@VM.SC.EDU>
>Subject: fumes
>the gas fumes from my 73 'b seem to be getting progressively worse.
>i beleive that i need to replace the gas tank (i suspect pinholes
>due to rust...). my question involves the vent from the gas tank that
>is in the trunk. i'm not sure of the technical name, but its the
>doo-hickey on the passenger side with a couple of hoses leading to it.
>is it possible that some of the fumes are coming from there? the po
>cut a couple of holes in the rear bulkhead for speakers that are no
>longer there, and i beleive that the fumes may be coming through from
>there.
>also, i know that i have the carbs set a bit rich, but the exhaust
>smells _very_gasoline rich. no black smoke or sputtering--in fact,
>the car runs quite well--so i don't think its due to the mixture being
>overly rich, but i'm not sure. any suggestions? the smell in the
>car is threatening to cause brain damage...
>thanks,
>-robert
> 73 mgb
Robert,
You may be overlooking another possible cause of your trouble.
Under the hood, on the passenger side, is an emissions control device called
the CHARCOAL CANNISTER. This is used to provide a non pressurized vent for the
fuel system. Fuel fumes are absorbed by the charcoal, so that no fumes actually
get to the outside of the closed emission system, if it is functioning
correctly. It could be that the charcoal is saturated with gas and you are
smelling the fumes from the front of the car. The vent for this charcoal
canister is from the base of the unit. There should be a hose that connects to
the anti run on valve.
It is possible that the floats in your carbs are not set correctly or the fuel
shut off jets are not functioning correctly and the excess gas is sent up the
vent pipe to the canister.
You might also check that the vent pipe from the canister to the vapor
separator tank is clear. The vapor separator tank is the thingy in the rear
passenger side fender space, with the two braided hoses. Locate the hose that
goes down through the trunk floor nearest the rear light, remove the hose from
the vapor separator tank and make sure you can blow air to the charcoal
canister. DO NOT USE YOUR MOUTH to do this!
Find someone who has a compressed air source if you don't have one yourself. I
have found on several cars that this line has been blocked with goo, and it has
taken quite a few pounds of pressure to clear, (20-30 pounds). You should also
be able to blow air through the separator tank to the gas tank and hear the air
bubbles coming up in the gas tank, remove the gas cap for this check.
There is a cheap way to over haul the charcoal cannister. If you are
interested, get back to me and I will give you the details. Good luck John
Bartholomew.
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E-mail <color><param>0000,0000,ffff</param>jdb70@juts.ccc.amdahl.com
</color>John Bartholomew Amdahl San Jose CA.
** 408-746-6361 07:00-16:00 PST. ** USUAL DISCAILMERS APPLY **
1969 MGBGT;1973 MGB;1974 MGB;1976 MGB;1979 MGB; 1972MGB daily driver.
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