After fixing mirade of other problems in the truck, there is this gas smelling problem that is eluding me. Want to see if I can fix it myself with help from you guys.
I checked for leaks all around, but I could not see any. I replaced all rubber hose portion of the fuel line. The gas smell seems to come from the engine bay area and can smell it inside the cab - I would tend to say more on the driver's side. I know that my vent line is dangling underneath the cab - not hooked up to any charcoal canister or nothing. But I am finding it hard to believe that it will give out a strong gas smell as this one. Also, I noticed that the gas smell comes only after running the truck for a while and after the engine is shut off. I do not notice any smell when the truck is running. I am guessing that probably some gas in the float bowel evaporates due to engine heat. Is this possible? I have a feeling the engine runs a little hotter, but I do not have a gauge yet.

What are your thought guys?

It is a 1979 truck with 302 engine, edelbrock 600cfm with electric choke.

 

You say your vent line is not hooked up and dangling underneath the cab? It seems likely to me that's where your gas smell is coming from. Hook the vent line up to the charcoal canister if you have one or run a longer vent line farther back under the bed. If your gas small goes away in the cab then you'll know.

You should have a vent line coming off the gas tank as well. That line should tie into the metal tubing that runs along the frame rail and connects to the canister via a rubber hose. If you don't have a canister and don't what to buy new you can probably find one at a wrecking yard. This would be your best bet for fixing any vent/gas smell problem. Aside from that what you can do is tie the vent line from the carb. into the metal tubing vent line from the tank just behind where the canister is supposed to be. Then place a "tee" back somewhere just off the tank and run a vent line back to the rear somewhere. You might get a slight gas smell from the back of the truck but it will be out of the cab.

Another culprit may be the fuel pump. If it's a machanical pump check the weep hole for signs of fuel coming out from it. If so, replace it.

If your carb. has a lot of miles on it the needle valves may not be in the best of shape or maybe some dirt in there somewhere. After shutting off the engine residual fuel pressure could leak past and over fill the float bowls causing a little spill over into the vent line dangling down below your cab. Just a thought. Good luck.

 

Actually, my carb does not have a vent line. The only vent line is from the gas tank that runs by the side of the frame and hangs free underneat the cab. I will see if I can get a charcoal canister.
The carb is new - about six months old. But I am not sure about the fuel pump. It runs fine, but I have reservations against it. I think I can smell gas around the fuel pump as well. I think I will go ahead and get a different fuel pump as well - something I know will not give out more than 6psi.
Will you post back after the changes.

 

Well, charcoal canister seems pretty expensive to me for a guess fix. So, I bought myself a vented gas cap. I will plug the vent line from the tank and see if I smell any gas. Will post back with the findings - plan to do it tonight.

 

Well, plugged vent line and installed vent gas cap. Don't seem to improve the smell much. Now, I know I got exhaust leak from the driver's side manifold. Not a very big leak. But the smell I get is distinctively gas. Can the exhaust leak be any factor to this? I am planning to buy headers soon to replace the manifolds.

 

An exhaust leak can give you an exhaust smell in the cab but I don't think your gas smell problem is coming from this.

You say your carb. doesn't have a vent line, however your carb. still needs to be vented. The carb. should have a nipple on top somewhere above the float bowl fuel level to attach a vent line. This was the vent line that should go to the canister that I was thinking about in my earlier post. By what you have said so far, I still belive your problem is coming from the carburetor vent. Even though there is no hose attached, there is still a vent there somewhere. My old 4100 carb. on my 64 Galaxy didn't have a nipple but a tiny, tiny hole in the top cover to vent the bowls.

You also say you notice the smell when the engine is shut off. With the engine off the fan is not spinning, no air moving through the engine compartment so it's very possible then that the gas smell is waffting up from the vent caused by increased evaporation from the heat off the engine as you allured to in your orginal post. If that is indeed the problem you'll need to run a vent line somewhere other than the engine compartment. Keep looking. Good luck.

 

Well, I finally ended up taking it to a local mech. He said that float was not adjusted, which he did. The gas smelll is less, but still not to my statisfaction. I will check to see if there is a vent. Mine is an Edelbrock 600 cfm with electrick choke.
BTW, found that I got a vacuum leak in my intake as well. New discovery today. Can this be a factor?

 

There isn't a bowl vent hook-up on the Edelbrock. A vacuum leak will make the exhaust stink and will allow fuel vapor smells to escape to where you can smell it.

 

The exhaust does stink. Talked to a few great guys on chat here at Ford-trucks. They recommended me to tighten the bolts down. I did that but, I still hear the truck rev up when I spray carb cleaner. Funny thing is that the truck was running might fine (expect for the gas smell) before I took it to the local mechanic. Now, it is not idling right and is hesitating when I go from stop. Runs fine once it reaches a certain speed. The shop I took it to supposedly have a good reputation. Anyway, they are taking it back for a re-check.