Strong Smell of Gas

[Stuart F.]

I have not had a chance to check in depth about this problem, but I know I will have to deal with it soon.

I recently changed the carb on my 63 L-76 to a correct model 3461S and, although it appears to be functioning quite well now, since my last fill I have experienced a very strong gas smell in my attached garage and it persists days after I have run the car and put it away. I have inspected everything top side including the carb and ruled them all out as the source. I have looked at the fuel pump and hose line to it and it appears ok. I crawled under the back to check the rear tank to line hose and too looks ok.

I can't imagine with all I went through before to limit this problem when I had a service replacement 3721SB on the car that I now have a much worse problem just since I changed the carb. I have the 2 way valve filler cap, the carb is still insulated to keep the temp down and I have standard (new) N/S and floats. There is no post shut down gas drip or percolation. The outside of the carb is perfectly dry. In fact,

I suspect that Uncle Sam's Ethanol has finally did in one of my fuel line hoses and made my situation dangerous.

Does anyone have an easy procedure guide to changing the rear hose without tearing the car apart? I believe that is where I will need to start because I can't verify its' integrity as easily as I can the rest of the fuel system. Darn, this would have to happen just before I was about to add my first tank full of non-ethanol.

Stu Fox

[Timothy B.]

Re: Strong Smell of Gas

Stu,

Check the gas tank for leaks around the center union.

Run the car low on gas and jack it up on the passenger side only to force the remaining gas to the drivers side away from the hose connection.

[Stuart F.]

Re: Strong Smell of Gas

Tim;

Thanks. I'll give it a try.

Stu Fox

[John D.]

Re: Strong Smell of Gas

Stu, As mentioned beware of any rubber hoses on your car that are not compatible with ethanol. Go to a good auto store and ask them what they have that is compatible for alky/ethanol.

Now I don't want to alarm anyone but I have a question. I was looking at a NOS 63, etc sender for the gas tank. I see this huge rubber "biscuit" in it. I said to myself last week. Wow!!! Wonder when this part is gonna start acting up with crappy ethanol. Don't really know so don't holler at me. Just quessing that it's going to be an issue in the future. I also don't know the composition of this rubber part. Maybe it's good enough for ethanol.
Accelerator pump could be the culprit Stu. Ethanol is killing those you know. But guys do sell ones for ethanol. I think they are blue in color.
At Corvette Carlisle a couple of people asked me if I had any leather accelerator pumps. Leather may make it thru ethanol whereas the stock rubber one swells up and craps out.
Now to wait for Clem to respond. JD

[Paul Y.]

Re: Strong Smell of Gas

I found that the ethanol had eaten the plastic fixture that the wire attaches to on the sending unit and I had to rebuild the sending unit with one from a parts unit. It has been OK for a year or more now. It smelled like gas a long time before it started to drip and I was looking for a bit. You have to remove the spare tire assembly to be able to view it and repair it. I'm not sure I can blame ethanol but I like to anyway.

[Jack H.]

Re: Strong Smell of Gas

Luckily, in my part of Missouri our premium is still ethanol free. At least for now.

[Doug L.]

Re: Strong Smell of Gas

Hi Stu,
Even though the rear end of the steel fuel line and the clamp for the tank-to-fuel line hose are on top of the frame rail and very difficult if not impossible to get to without raising the body, that neoprene hose that connects the tank to the steel line runs down off the frame rail and should be accessible from under the car, at least at the tank-end. Since the clamp on the neoprene hose at the tank connection is the lowest point, any fuel leak in that hose should be evident at that low point. You should be able to feel moisture at the low point if the leak is in that hose.

Is there any possibility that fuel got spilled into the retainer boot around the fill-neck of the tank? If the spout in that retainer was not positioned correctly, fuel might sit in the retainer until it evaporates instead of draining to the ground.
Doug

[Stuart F.]

Re: Strong Smell of Gas

Thanks J.D, Paul, Jack and Doug. You've given me some pointers on what to check. The garage is retching with the smell.

I know the carburetor is not at fault as I just finished it a few weeks back and everything looks good. I use only leather accelerator pumps because every special pump I have seen made with Ethanol compatible material is of the 13/16" size for Edelbrocks, not the 11/16" used in Carter AFB's.

This is surely something I can't easily see or locate.

Thanks again;

Stu Fox

[Michael M.]

Re: Strong Smell of Gas

Stu, to rule out the new carburetor for sure I would install the old carburetor when the smell was not present. If you still have the smell then you know for sure its not the new carburetor.

[Bill W.]

Re: Strong Smell of Gas

Stu, I had the same problem in the past, turned out to be leakage between the fill neck and tank. The fill neck is held on the tank by nine screws holding a gasket between neck and tank. The gasket is cork and becomes brittle with age. Adding to the problem is warpage of the fill neck flange.
Remove the fill neck and I think you will find the source of your leak. A small anvil and some light hammer work will strighten the flange. A new gasket will complete the job. The tank has a reinforcement ring to prevent it's warpage. Good luck. Bill

[Harry S.]

Re: Strong Smell of Gas

Did the gasket on the fuel pump pop a leak?

[Stuart F.]

Re: Strong Smell of Gas

Thanks Mike and Bill.

Mike; I expect either carb to vent all of the gas from the bowls within a few days. This; however, is going on two weeks now and the smell has not gotten any better. I'm more inclined to follow the advice to look at the line from the tank or the filler neck, as Bill suggests due to the fact that there is still a fair amount of gas in the tank. Enough to feed this for quite some time.

Bill; Not being outside in the garage, can you tell me if the neck can be accessed from the top or do I need to drop the spare tire housing and tank?

Stu Fox

[Stuart F.]

Re: Strong Smell of Gas

Harry;

If it did, I can't smell any gas or feel/see any in that area. Also, there is no gas smell on the dipstick. I will check again to be sure.

Thanks;

Stu Fox

[Harry S.]

Re: Strong Smell of Gas

Harry;

If it did, I can't smell any gas or feel/see any in that area. Also, there is no gas smell on the dipstick. I will check again to be sure.

Thanks;

Stu Fox

A few drops of gas will permeate a closed garage.

[Bill W.]

Re: Strong Smell of Gas

Stu, The neck can be removed from the top once you work the rubber splash shield up over the top of the neck. Note that the nine machine screws all have rubber "O" ring gaskets on them, replace these with new. Good luck. Bill