Gas Odor

P

philip t. dickinson

New member
Nov 2, 1997
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I have noticed a raw gas odor after having driven the coach and then
stop. The gas odor seems to be present only after the coach has been
driven and disappears in about 15 to 20 minutes. It is never there
while the coach is stationary. I had only a half
of tank of gas at the time.
P.S. neither myself or my wife had anything unusual for dinner!

Any ideas on where to start to look would be appreciated

Thanks
Phil
78 Royale
 
I need help solving a raw gas odor problem. After driving the coach and
stopping I smelled a raw gas odor for 20 to 25 minutes. There is only a
half of tank of gas. Any help on where I might start would be
appreciated and no my wife didn't have anything unusual to eat!!!

Thanks
Phil
78 Royale
 
Hi Phil,
I dont know if this is the same on all GMCs but I had
a gas odor/leak on mine. Drivers side rear bogie had a
gas filter mounted in the wheelwell behind a steel box.
I never knew it was there until the hose started to
leak. Just a thought.
Rob Teed 74 Painted Desert

> -----Original Message-----
> From: owner-gmcmotorhome
> [mailto:owner-gmcmotorhome]On Behalf Of Philip T.
> Dickinson
> Sent: Sunday, June 27, 1999 7:01 AM
> To: gmcmotorhome
> Subject: GMC: Gas odor
>
>
> I have noticed a raw gas odor after having driven the coach and then
> stop. The gas odor seems to be present only after the coach has been
> driven and disappears in about 15 to 20 minutes. It is never there
> while the coach is stationary. I had only a half
> of tank of gas at the time.
> P.S. neither myself or my wife had anything unusual for dinner!
>
> Any ideas on where to start to look would be appreciated
>
> Thanks
> Phil
> 78 Royale
>
>
________________________________________________________
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>I need help solving a raw gas odor problem. After driving the coach and
>stopping I smelled a raw gas odor for 20 to 25 minutes. There is only a

There are a number of places where these things leak. If the odor is coming
from under the hood then its most likely the fuel pump, fuel line from the
pump to the carb or the carb itself. I have had all three leak. The problem
is finding the leak. The hot engine causes the gas to evaporate as fast as
it leaks so you probably will not see a wet spot. But, in time, it will
leave a residue or get worse. When the engine is cool, start it and then
shut it down before it has a chance to heat up. Maybe you can see the wet
fuel while your engine is still cool.

I think the fuel pump was the hardest leak for me to find. I didn't find
that one until it got so bad that fuel was gushing out of the vent hole.
Fuel pumps are pretty cheap so if you don't see any obvious leaks you may
just want to take an educated guess and replace the fuel pump.

With regard to the carb. Even if there is not a leak, I think there is
still a substantial amount of gas that evaporates out of the float bowel
after a hot shutdown. I don't know if this is normally a problem when
things are working right. I suspect that the gasket or maybe the needle
valve on my carb was leaking. I cant say for sure because I fixed the
problem by replacing my carb with the Howell closed-loop TBI system. No gas
smells from the TBI system.

You may also want to check out the rest of your fuel lines. Sooner or later
all of the rubber in the fuel system rots out and needs to be replaced.
Sometimes its hard to tell for sure exactly where the smells are coming
from. There may actually be more than one small leak.

Dave
73 Sequoia
 
>a repair on my cracked one, and spending the change from $140 on good
>scotch! Any recommendations on what I should use...

Have you tried Johnny Walker Blue Label? I have a rich friend who buys
it...I do believe that it might just be worth the difference.

Travis
 
Hi Emery,
Thanks for the info...I found it on the maiden journey
to the Keys. I thought it was a gas filter. Guess I'll
have to clean that thing out huh?
Rob Teed 74 Painted Desert

> -----Original Message-----
> From: owner-gmcmotorhome
> [mailto:owner-gmcmotorhome]On Behalf Of
> EMERYSTORA
> Sent: Monday, June 28, 1999 7:32 PM
> To: gmcmotorhome
> Subject: Re: GMC: Gas odor
>
>
> Rob -- the last I knew the thing inside the box by the driver's
> side bogie
> wheels is not a fuel filter but rather it is a gasoline vapor/liquid
> separator. The hose from the gas tank often contains both liquid
> gasoline
> and gasoline vapors. The vapors go through a hose to the
> pollution control
> cannister up front (probably under the passerger seat on your
> GMC) where they
> are drawn by a vacuum line into the carb and there is a return
> hose from the
> separator for the liquids to return to the gasoline tank. This unit
> sometimes gets gummed up and can be dissambled for cleanup to get
> it working
> properly.
>
> Emery Stora
> 77 Kingsley
> Santa Fe, NM
>
________________________________________________________
NetZero - We believe in a FREE Internet. Shouldn't you?
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Re: vapor liquid separator...

>there is a return hose from the separator for the liquids to return to
>the gasoline tank. This unit sometimes gets gummed up and can be
>dissambled for cleanup to get it working properly. Emery Stora

There is a note in this months GMC Motorhome News, where Wes says he is
offering a metal version of the separator for $140 because the plastic
version everyone has, is 25 years old and both the hoses and the
separator tend to crack and leak.

Seems like replacing the hoses, cleaning, and epoxi might fix quite a few
and Wes will probably still sell enough metal ones to make his money back
and make the part available for the community. I'm thinking about trying
a repair on my cracked one, and spending the change from $140 on good
scotch! Any recommendations on what I should use...

Regards,
John

- --

"I do whatever my Rice Krispies tell me to..."
John said, from inside a 1974 Glacier on the
Potomac, just north of the White House.
 
I just took my fuel vapor separator apart three times. I cut it open
with a utility knife. Inside is a ball just smaller than a ping pong
ball and a sliding needle that closes off when the ball floats up. Mine
was slightly deformed ant the ball wasn't floating up. Out came the
hair dryer and a three inch clamp. I then tried to glue it back
together again. JB Weld is the product that worked. I had all my parts
laid out in an old drawer that the kids then dumped and took for a maze
for the pet mouse. Nothing is sacred.

Walter
78 Royale
 
Emery, My separator is a sealed unit. If I remove the plastic welded cap,
is it a big PITA to reseal the thing?
Dick 75 PB in Atlanta

>Rob -- the last I knew the thing inside the box by the driver's side bogie
>wheels is not a fuel filter but rather it is a gasoline vapor/liquid
>separator. The hose from the gas tank often contains both liquid gasoline
>and gasoline vapors. The vapors go through a hose to the pollution control
>cannister up front (probably under the passerger seat on your GMC) where they
>are drawn by a vacuum line into the carb and there is a return hose from the
>separator for the liquids to return to the gasoline tank. This unit
>sometimes gets gummed up and can be dissambled for cleanup to get it working
>properly.
>
>Emery Stora
>77 Kingsley
>Santa Fe, NM
>
 
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