Quadrajet Question, Fuel smell

[Lawrence R.]

My 73 after driving smells up the garage with gas fumes, I have read about the bowl leaking and mine after sitting a day or so takes a while for it to get gas. I have replaced all fuel lines with the new type rubber, & canister filter. Any information would be very helpful. Thanks

[Timothy B.]

Re: Quadrajet Question, Fuel smell

Lawrence,

There is a one way check valve that pushes into the center of the carburetor gasoline filter on those Quadrajets. This valve is supposed to keep fuel from draining back out of the carburetor because I THINK the inlet is on the bottom. The evaporation on this new gas is different than the old stuff so that's why the carbs are empty after they sit for a few days. My 67 smells the same way, keeps the wife out of the garage..

Just a suggestion, If you can go to a Barnes and Noble book store in the transportation book section there are books on the quadrajet overhaul and the gasoline small may be mentioned and give you some things to think about.

[Lawrence R.]

Re: Quadrajet Question, Fuel smell

Thanks Tim, will check the valve and as for the smell my wife has her
Trailblazer next to my Vette and she may just move me out if I can't get it fixed. The smell also gets into the house at times.

[Edward J.]

Re: Quadrajet Question, Fuel smell

Larry,sometimes the vapor canister is a problem if the vaccum diafram fails,which allows the vapors from fuel tank to escape when shut down through the bottom of canister, it is a closed system so theres not many places for the vapors to escape, if you have have a set of ramps, see if the fuel smell is in the area of the canister.

If you suspect a carb. bleeding down, there maybe other indicators, hard starting after a shut down for 10-15 minutes and black smoke out tail pipe. or long cranking time after sitting for a few days(taking time to fill float bowl with fuel).

The check valve Tim is taking about in the fuel filters on quadrajets I think started in the mid 70's and was used if the car rolled over,it stop the fuel from flowing to carb. in case of a fire.

[Chuck S.]

Re: Quadrajet Question, Fuel smell

Thanks Tim, will check the valve and as for the smell my wife has her
Trailblazer next to my Vette and she may just move me out if I can't get it fixed. The smell also gets into the house at times.

Tell her it's a new perfume...Ode de Muscle Car; a little bit behind each ear and she'll be irresistible. Oops...No, probably a bad idea.

[Lawrence R.]

Re: Quadrajet Question, Fuel smell

that would be a great perfume for me but not her

[Edward J.]

Re: Quadrajet Question, Fuel smell

Larry one last detail, make sure the your gas cap is of the sealed type,not vented.

[Lawrence R.]

Re: Quadrajet Question, Fuel smell

Edward
I do not smell anything down by the canister and I have the non-vented cap
Thanks

[Jack H.]

Re: Quadrajet Question, Fuel smell

A couple of issues here...

First, because your car has a carb (vs. your wife's fuel injection), fuel in the float bowl HAS to be vented. Therefore, some evaporation is normal and just part of the technology of yesterday that's no longer applicable to modern day cars whose FI systems are fully sealed from the tank to the injector... You live with this!

Second, the way QJets are designed/built, there are 'plugs' in the bottom of the idle mixture transfer slot. These were rather notorious for leaking and any decent carb rebuilder will remove the factory original plugs and seal with some form of permanent sealant, like epoxy.

Was this done on your carb? If not, it's possible for the carb to be leaking internally with excess gas spilling into your intake manifold. That WILL increase stray fumes...

Third, when the sealed tank came along with the VRS (vapor recovery system), it required there be adequate unused space in the fuel tank for vapor expansion. Some, are used to 'topping' off their tank (continue to fill it with gas after the pump's automatic cut-off kicks in)...

It's possible to OVERFILL the gas tank if you do this! Then, if you take a warm/hot car home with an overfilled gas tank, it's possible for it overwhelm the air/fuel separator in the tank and trickle raw gas into the line feeding your VRS (charcoal cannister). I can GUARANTEE you that will result in substantial fuel vapors in the garage as the car cools down!

The only time you want to 'top off' the early VRS cars is when you're on the highway cruising and you KNOW you're going to drive an appreciable distance after you've filled up. If you're in the practice of storing the car with a full tank of gas, then STOP filling when the pump's automatic cut-off kicks in.

[Lawrence R.]

Re: Quadrajet Question, Fuel smell

Jack, thanks for the information and one thing I don't do is fill the tank unless I am going a short trip. I know we are not used to the old carb smell but this is worse than I remember, so I guess I will remove the carb and seal it up. Again Thanks to you and all the lvery nice people here.

[Jim T.]

Re: Quadrajet Question, Fuel smell

Since you have replaced all the fuel lines you might check all the connection locations and insure you have no leakage. The connection for the fuel return to the gas tank is not easy to get to.

[Michael W.]

Re: Quadrajet Question, Fuel smell

My '73 with original carburetor will start on the first turn of the key after sitting untouched over the winter, never mind just a day or two. No need to crank and crank trying to refill the bowls I frequently use E10 fuel so the stories about it evaporating in a few days are untrue. The car does have a 'hot engine' and exhaust gas smell after a long drive but certainly not a raw fuel smell of any type.

You may want to inspect the check valve ass'y on the left upper side of the gas tank. This assembly is made of fairly brittle plastic and will leak raw fuel on the muffler directly below if cracked.

[Michael G.]

Re: Quadrajet Question, Fuel smell

I have been able to reduce some of the stink by activating the choke once she has cooled down enough to actuate it. It's not a complete solution, but a noticable reduction on mine.

[Phil D.]

Re: Quadrajet Question, Fuel smell

Wow, useful stuff. My brother's 72 has the same issues but my cars and my brothers are stored in a separate building. Smell has only really been disagreeable when he takes it home and parks it in his garage overnight. We're going to rebuild the carb soon anyway because it seems also to have a weak accelerator pump. If that doesn't fix the smell then we have some other things to check.

[Robert R.]

Re: Quadrajet Question, Fuel smell

...you also may want to check the hoses that lead to the canister. Mine smelled every time I drove and put it back in the garage, and could not reason why. Until I happened to check with a flash light and noticed the hose at the canister cracked and a definate gash on its side.
once the hose was replaced, no more smell. This fix also cleared up a bogging effect while accelerating.
Bob