Gasoline odor -- too strong.

[Mac]

Hello Folks, it's been a while since I posted here. Quick update, I did a resto on a '65 mustang coupe from 2005 until Oct. 2008. The engine (rebuilt by a local rebuilder in Fall 2008) is a 1978 200ci with engine head D7BE-6090-AB and block D8BE-6015-GC, with a manual Carter YF carb with spacer. My 16 year old son drives this car for his personal car and he loves it, but as such, Im always checking it and making sure everything is in good order. For the past few months, we've noticed a gasoline smell when he pulls it into the garage and it sits for a minute or two. Things Ive checked include the fuel line from fuel pump to the tank. Also checked the rubber nozzle hose inside the trunk. All dry, no leaks. Fuel line from pump to carb. All dry, no leaks.

I decided to replace the fuel pump just in case the diaphram may have busted. Replacing the fuel pump didnt help -- and I checked the fitting on top of the fuel pump, no leak there, bone dry. I removed the carb and installed a new carb to spacer gasket and a new spacer to manifold gasket. No leaks but still a strong gasoline odor. I rebuilt the carb with a rebuild kit and the float was set to the height recommendation, etc. I've adjusted the carb according to the Carter YF documentation I have. Other than this problem, car drives well so long as its allowed to idle for a couple of minutes when the weather's cold. Just not sure what else to check now or if maybe I should just buy a new/reman carb. Suggestions welcomed. -Billy

 

[The Plankster Prankster]

in my experience, some other common failures include:
slow leak in gas tank. can be identified by wetness on part of tank, or by "watermark" effect
problems in tank's vent line
i don't know how well you inspected the fuel lines, but on my car i had one rust through in a well-hidden area (behind fender lining). just because the rubber parts are fine doesn't mean the steel line is ok

also consider that if the car is idling too rich, that could be enough to produce a strong fuel odor

 

[Mac]

Thanks for the advice prankster. All fuel lines are new (less than 1 1/2 years old). Perhaps I need to revisit the fuel mix, it may be running rich.

 

['68falconohio]

Only smell it when the engine's shut off at full operating temp? Could it be the fuel in the line to the carb is heating up(increasing pressure in line) and overcoming the needle in the carb? A lot of guys have problems with this causing poor hot starting conditions; maybe in a garage you can smell that fuel going into the intake? Open element air filter, by chance?

 

[Ronbo]

It uses a vented cap correct? I've had the mentioned fuel line problems and that was where my smell came from (behind the fender as well, AND rusted through). I'm thinking if you park the vehicle in the garage hot with a vented cap you will have some gas smell? Mines outside so I cant tell. I do know if its parked on an incline when its full I have fuel coming out the cap. Just something else to look at.

Ron

 

[powerband]

Without vapor recovery canisters and with vented carbs and crankcase road tubes, I don't see any way to prevent gas smell hangover. The 3 carb Offy setup with steeple vents on 1904 bowls and open air cleaners is the worst of mine. Fter shutdown the heat of the engine evaporating gas makes garage reek. I usually try to let it cool before putting away...

 

[Frankenstang]

Along the lines of a couple other places to check...
Before I replace the tank in mine, I had a good degree of surface rust on the top of the tank. I changed the fill hose prior to biting the bullet for a new tank, but the smell remained. I'm pretty sure I had enough rust on the top outer surface of the tank (aka trunk floor) that the metal had become more pourous than I would have thought...continual gas smell in the cabin clinched me getting a new tank.

After swapping the tank, I used the readily available American Designers (N American made) version sold by most the part stores, I still had smell build up in garage. Turned out that was from the crappy foreign made sending unit included in the kit purchase. It was seeping around the gauge electrical post grommet on the sending unit. Was hard to see the stain initially, and summer time with evaporation...it was not leaving any puddle on the ground (vice grips on the post and tiny open end on the nut tightened/resolved the leak). Otherwise I would have to agree with the thoughts on vented tanks. Although, :tabu: scarry warning coming...my brother's 77 f150 custom with ~30k original miles burnt to the ground before christmas because of a leaking (read cheap) inline filter...certainly best to be safe when double and triple checking for fuel leaks...varnish stains were the main indication for me when visible.
Good luck!

 

[Mac]

Good advice to ponder everyone. The gas tank is new along with so many other components, except the 33 year old carter carb, which got a rebuild a couple of years ago. When I bought the car, it had no air breather. I bought one at a boneyard from a 1977 Ford Maverick. It fits great but there are 2 holes along the side of the breather for suction lines which I dont whether they apply to my engine setup or not. Should I tape those holes off ? The oil fill cap on the back top of the valve cover has a hole on top but is filled with a foam filter.

 

[ludwig]

If you mean the snout of the air cleaner when you say 'breather', at least one of them would be for the flapper pull-off in the snout, aka 'snorkel'. When closed, it pulled warm air in from a stove near the exhaust to speed up engine warming. In the open position it let in cool fresh air. And when it flapped closed, the gas and PVC fumes stayed in the air cleaner. If there is a larger hole underneath the snorkel, this is for the warmed air to enter.

 

[Mac]

Yep, Im calling the air cleaner the breather. Im not talking about the snout though, Im referring to the hole in the side of the cleaner above spark plug #4. There is also a hole on the opposite side , but Im not sure what either hole is for. The snout had no snorkle when I bought it, so Im not sure where the other end of the snorkle would rest in order to get the heat from the exhaust manifold, or if that is important.

 

[ludwig]

The one on this side is probably for the PCV line or some sort of fume recycler or line to a charcoal cannister. Same on the other side. There would be a little tin collector on top of the exhaust manifold somehow with a pipe up to the underside of the snout/snorkel/breather.

 

[tony1963]

My vote, from experience, is that fuel is heating up in the carburetor and overflowing into the carburetor throat, venting out through the air cleaner.

A 65 Mustang would not have a vapor canister. The fumes vented to atmosphere.

My second vote would be a bad gas cap seal.

 

[Marine05]

The holes in either side of the breather are for vacuum lines that ran emissions for the smog pumps on the later model cars. I have the exact same breather on my 81, but now that I have no emissions stuff on it, no use for them. Those aren't your problems. Mine are not blocked or anything and No gas smell. The biggest problem that I have had withgas smell is the rubber grommet that goes into the fuel tank from the filler neck, if it is not seated right, there will be a gap causing serious fuel smell.

 

[dbowl]

I’m with tony1963 on this one. When you park it, pull the air cleaner and listen for gas (a hiss) boiling over in the carb. Sounds like water dropping on a hot stove/flame. You can usually see it too.

 

[Ronbo]

Gas cap....gas cap....gas cap.....

No hot start issues right?

Also, sounds like that is not the original air cleaner. Like the other guys pointed out, those holes are for emissions that did not exist in 65 (I think California started somewhere in there).

Great car and great experience for your son! He's a lucky guy!

Ron


PS I now see the casting numbers and understand the air cleaner a bit better.

 

[Mac]

When my son pulled the car in this evening, I had him kill the engine and I quickly removed the air cleaner. A small wiff of vapor smoke came out of the top of the carb and I could hear a hissing sound inside the carb. I believe that may be the odor issue. My nose could detect only a faint smell at the gas cap which has a rubber seal, so I dont think there is enough to say that the odor could be smelled within an enclosed garage, at least not the what we're experiencing. Got to be the fuel burning in the carb or intake.

Ron - No warm/hot start issues.

Someone mentioned 'non heat transfer' spacers and heat shields. I suppose that would make a good start.

 

[Ronbo]

Could be just what the fellas are saying. You saw/heard it so how do you fix something like that? I know the Holley on the truck likes to puke once in awhile but not often. I'll just kick back and wait on the fix :chill: This one is beyond me.

Ron

 

[dbowl]

I doubled up on the gaskets on each side of the spacer between the intake and carb. Not because of the odor issue but because I could be going down the road and the thing would bog and then die. Other times I would run it to the grocery store and when I returned to the car, it was impossible to start. The fuel was boiling over and flooding out. The doubling up on gaskets and an adjustment on the float solved that problem, but I still have “the smell in the garage” issue. Not sweating it though. The car is 40+ years old and one of those things I just expect. Glad to hear you have probably pin-pointed your problem.

 

[mannella]

I had this problem and removed the heater hose that went through the carb spacer and hooked them together. I ran a hose from the spacer to the front of the car to let a little air flow help cool the spacer. I haven't had any problems since. I think this summer I will remove the hose to the spacer to see if I really need it. I should mention the car is a 65 mercury comet so I don't know if the set up is the same.