Gas smell

[Bluejeansthe5th]

Thanks to this site and assistance from folks my 87 Fifth runs great with Electronic Spark and original carb in place. However, I now smell raw gas, and in the area of the charcoal canister, especially after shut off. I checked for vacuum on the hose at the top of the canister with the engine all warmed up; no vacuum. I did put a Mighty Vac on the valve on top of the canister and it held vacuum (test from the FSM).
Does any guru know if vacuum is present from the temp valve (which this line is connected to via the underhood label) only at cold start up? I know this valve also is in the air pump system. Does not look like the canister is an easy removal due to being under the coolant recovery bottle. As I remember the purge from the canister occurs on start up, don't think that is happening.

 

[Aspen500]

The canister only purges at part throttle while driving the car. Should be no vacuum at the canister at idle. Also has to be above a certain coolant temp.

 

[BudW]

Usually if there is gasoline leaking from charcoal canister then, in most cases, your float level is too high, or float sunk and/or trash is keeping the carburetor needle n seat from closing. The fuel is going in from the large vapor hose (as well as leaking fuel externally from carburetor and/or leaking into the carburetor itself.
The good news is once you fix it, you fuel mileage will greatly improve.
BudW

 

[Mikes5thAve]

The metal lines also like to rust over the frame along that area behind the wheel which is the most common cause of smell around there.

 

[Aspen500]

If the canister isn't purging it can get saturated with fuel vapor and then you'll smell fuel also.

 

[Bluejeansthe5th]

Usually if there is gasoline leaking from charcoal canister then, in most cases, your float level is too high, or float sunk and/or trash is keeping the carburetor needle n seat from closing. The fuel is going in from the large vapor hose (as well as leaking fuel externally from carburetor and/or leaking into the carburetor itself.
The good news is once you fix it, you fuel mileage will greatly improve.
BudW

Thanks for the reply. I don't see any leakage at all, just odor. I see no gas leaking, anywhere. I did rebuild the carb last year, might need to re-check float level. I wonder if it would be useful to disconnect the large vapor hose at the canister and see if gas is present. I'm not sure if it applies to cars with the EVAP system, I've heard a high float level, allowing gas in the intake manifold after shutdown causes hard starting. Let's say I go to the Post Office and mail a letter upon coming back out, the car cranks literally for a second and starts; no application of the gas pedal and runs smooth. I do have the electrical connection for the fast idle disconnected as I understand it makes the idle high on hot start up for a duration and I don't like this.

 

[Bluejeansthe5th]

If the canister isn't purging it can get saturated with fuel vapor and then you'll smell fuel also.

Thanks for that info. I think I will try and remove the canister and see if it is saturated. I don't try and "top off" when the gas pump clicks off, but wonder if PO's did that.

 

[Aspen500]

By saturated I didn't mean with raw fuel, only fuel vapor.

 

[Hayzoos]

A problem I ran into after rebuilding my carb was at the float valve. The rebuild kit I had came with a valve needle that had a black plastic piece while the original did not, otherwise they looked the same. The kit I got was labled ethanol compatible. Well, true except for that plastic piece. It deformed and would cause the valve to not close reliably. I simply removed the plastic piece and it works fine now.

 

[BudW]

The parts might be (or might not be) Ethanol compatible - but I still don't recommend using Ethanol because it takes about 10% more of it to get the air/fuel ratio correct and our cars just can't handle that much difference - without physically re-jetting them.

I know that both of my cars run like #$%^ if you don't use 100% gasoline in them. They will both start and run - but feels like is running with a couple of spark plug wires disconnected. This is one thing about converting to fuel injection will allow me to use Ethanol for it will adjust to the fuel, better.
BudW

 

[Aspen500]

Where fuel injection can compensate for ethanol content or different qualities of fuel, carburetors can't.

 

[volare 1977]

I have seen canisters before that actually were saturated with gas.

 

[Oldiron440]

I have seen canisters before that actually were saturated with gas.

Same here

 

[BudW]

I have seen fuel dripping out of the charcoal canister before - but that is typically from a stuck, or sunk, float (or trash in lines, etc.).

 

[Bluejeansthe5th]

I have seen fuel dripping out of the charcoal canister before - but that is typically from a stuck, or sunk, float (or trash in lines, etc.).

I have checked carefully and there is no gas dripping, just odor. As Aspen 500 said, the canister may be saturated just with vapor. I appreciate all the help.

 

[Kramer79]

Any updates on this problem? My slant diplomat does a similar thing, after rides, gas smell bad. On older cars with no evap they used a vented cap? Thanks…