Living with Carbs Question

[Halm]

My 1970 E with a RS spec engine had carbs (first Webers then PMO's) so I know what life is like performance wise. One of the daily drawbacks was that my garage smelled like gas all the time, with both brands of carbs.

As I plan my SC's descent toward becoming a semi-dedicated DE car, I am thinking about carbs again. However my current garage is directly under our bedroom and a gas smell would be totally unacceptable. So my question is: Does living with carbs always mean there is a gas smell present or was the '70 not setup properly?

[steve911T]

That sure sounds a bit strange. My 70T with Webers never makes my garage smell like gas. My garage is a 20x20 with complete insulation so I would have to think if there was a potential of smelling gas, I would surely smell it. I am also using the original air filter/cover assembly. Good luck. Steve

[Rich Lambert]

There is no way you should smell gas. I had that same issue, and with a propane fired hot water heater in the garage, I had to deal with it.

I went through every fuel connection on the car and found more than one leak:
- fuel inlets on both carbs (this also led to finding gas between the rain shield bases and the carbs)
- fuel outlet on pressure reg
- gas gauge sending unit
- blocked off gas heater outlet on the fuel tank

[vwbobd]

Originally Posted by Rich Lambert

There is no way you should smell gas. I had that same issue, and with a propane fired hot water heater in the garage, I had to deal with it.

I went through every fuel connection on the car and found more than one leak:
- fuel inlets on both carbs (this also led to finding gas between the rain shield bases and the carbs)
- fuel outlet on pressure reg
- gas gauge sending unit
- blocked off gas heater outlet on the fuel tank

Why are you heating your hot water ??

[ppanagis@gmail.]

I have a 73.5 T engine on webbers....Gas smell is impossible to get rid of. all gas lines are secure no leaks sending unit has a new gasket... But ???

Blocked off gas Heater outlet? what is that?

[Rich Lambert]

Originally Posted by vwbobd

Why are you heating your hot water ??

I actually thought about that after I posted it, but decided one would notice...lesson learned.

Originally Posted by ppanagis@gmail.

I have a 73.5 T engine on webbers....Gas smell is impossible to get rid of. all gas lines are secure no leaks sending unit has a new gasket... But ???

Blocked off gas Heater outlet? what is that?

The outlet for the fuel line that used to feed the Wabasto gasoline heater.

[Scott R]

I always had this as well with my webers. I was told after posting the issue here that it was normal due to the venting of the carbs.

[RWebb]

to Rich's list add:

- emissions vapor hoses loose or cracked
- charcoal emissions vapor canister cracked or missing entirely
- fuel tank cap gasket cracked or hardened

once you check and/or fix the above you should NOT have any strong gas odor at all - certainly nothing like you describe.

I say "strong" above b/c some people are "super-tasters" with much higher abilities to taste food aromas or wine than others - I'd bet that applies to gas & benzene too. Pregnant women sure seem sensitive to gas odors. A brand new 1970s car will always have more emissions at rest than a 2010 Lexus, etc. Modern cars contain small pumps to collect vapor, condense it, and return it to the tank. A modern car emits less pollution driving 60 miles than an older car does when sitting still.

Other than that, fix the fuel & emissions systems and you'll be fine.

[moneymanager]

My 74 with PMO's has no gas odor at all. It used to; I added another gasket to the fuel tank lid and the odor disappeared! Gas smells can come from a lot of places.

[2.70Racer]

Carbs don't smell. Leaking gas smells.

[rfn026]

Try to find a shop that checks for emissions. They should be able to use the probe to check for hydrocarbons. Check all of the connections from the front to the rear. You'll see the HC numbers shoot sky high at some point. That's where your smell is coming from.

Richard Newton
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[Trackrash]

I have had carbs on both my cars for 30 years, both zeniths and webers.

If I smell gas, I look for the source.

Now if I take the air cleaner off that is a different story.

[Davie Boy]

I'm relatively new to carbs and have the same issue. I haven't been told this directly by my mechanic, but I'm kinda getting the feeling that the gas smell is kinda like oil leaks: that it's a fact of Porsche life. You can either live with it (assuming it's not at a dangerous level) or put all kinds of time and energy (and money) into getting it 100% dry. I'm currently living with it... but then again, my carbureted 911 sleeps outside (covered, of course.)

[lindy 911]

I have found that if you put a switch in the fuel pump lead and turn it off a block from home the engine will burn off any pressure left in the pump circuit. Float needles will seep fuel and flow into the intake manifolds. You can smell it. It's an easy fix for at least part of the problem.

Lindy