At 06:53 PM 2/12/96 -0800, you wrote:
> On Feb, 12 1996, Mon 8:55:00 AM at Palmer, Lew wrote:
>
>>But a *positive* pressure? This too could be a plugged gas cap, but I
>>don't understand how positive pressure could develop except by the gas
>>expanding thus expelling air.
My '74 B is usually parked on a slight incline (with the nose up) while at
work. Its petrol tank is supposed to be vented only through the vapor
recovery system. The openning for this is on the upper portion of the tank
on the right-hand side, close to the filler spout. On hot days (in
Healdsburg, CA) in the summer the tank indeed does develop a positive
pressure from the fuel expanding. A few times, when the tank was near full,
the pressure was great enough to drive some fuel into the vapor openning
(again because I was parked on the incline with the vapor openning at the
rear) and after firing her up and driving for a few miles, the fuel would
begin to spill out of the charcoal canister all over the engine compartment.
Once I deduced what was going on, I drilled a small .062 hole in the gas cap
seal to vent the air which was building up. I have never had this problem
again. And I've pulled the cap off now and then and never had the whoosh of
escaping air repeat because the pressure was relieved!
Craig Wiper
early '74 B
craigw@sonic.net
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