Help -gas smell

First of all - I prefer to think of myself as semi - mechanically disinclined - if this helps in your diagnosis and suggestions for a solution.
The problem is a gas smell in the garage after I drive the car and pull it into the garage and shut it off. The driving is only short distances since I'm still trying to get the title straight with the DMV. Since this could take a a while I don't want the battery to go dead while I wait so I just zip around the neighborhood.
It's a 1776cc with dual 40 Solex carbs.
Is it because it only gets a ten minute run, is it common or what? Any thoughts would be appreciated.

Do you notice any puddles or drips under the car when you move it ?
Do you smoke ?

Do you have a small vent hose coming from the tank filler neck ?
Does it have a small black and white dime sized one way check valve?
Do you also smell the gas on a left turn ?
The smell may be gas coming out the vent hose.....Alan

I just went through this BS today on my car - every time I drove around with the gas tank over 1/2 full it would stink of raw gas when in the garage. Sure enough, the gas gauge sender gasket was leaking. Made up a new one of rubberized Cork and that cured it. I just came back from a 2 hour run, filling it before I got home and no "weeping" at the sender - Hurray!

Try to isolate the smell to the back (engine) or the front (gas tank) - that way we can help you zero in on the cause.

Alan and Gordan hit on two problems I have encountered- firstly, the vent tube sloshed out fuel every time I went around a corner until I had John install a check-valve. Later the sending unit gasket began leaking- the cork replacement is definately better than the rubber original. I also put nylon washers under the sending nuit screw heads to keep gas from coming up the threads. When the sending unit is off, check the taps into the tank (for the screws) for burrs which will cut the gasket- If you find 'em (I did), file them off flat.

Thanks guys,

I'll check it out over the weekend and let you how I make out.

Joe

I had a rubber gasket originally, and those little nylon washers under the screw heads when it was leaking and couldn't decide if they were leaking or not, so when I made up the cork gasket I made the screw holes a little tight, then used little fiber washers under the screw heads.

Probably never know if the nylons were OK or not, but it's not leaking now and that's what counts!

As I posted on another thread, I jsut put the first two miles on my car, which is still being built. I had the same problem; BIG-time gas smell in the garage last night as I worked on the punctured oil cooeler (yes, it was an ill-fated two miles!) The smell originates from the engine compartment though. I chased all of the gas lines which are mesh braided, and no wet spots. Taking a whif of the carb. filters produced the strongest concentration of odor. Any thoughts, or experience?
-Tim

Tim are you possibly just running really rich? Are the filters cleaned? If there aren't any leaks it could be just rich mixture.

tim, could be your float level not cutting the fuel off and its
weeping into throat. how hot was your car? sometimes fuel is
"boiled" off because lines, exhaust etc..have been routed wrong
and the fuel bakes on engine shutdown

Tim:

It could be running rich as Mike mentioned......mine runs rich, too, but now I only get gas smell when I'm coming to a stop and the exhaust catches up with me!

I had raw-gas smell like yours the first few times I ran my new engine (running Dellortos) and checked all over everything - hoses, connections, clamps, the works). It also seemed strongest right around the carbs, especially on one side. Never did find anything wrong and it seemed to go away after I drove it a few more times.

If you don't have choke butterfly's in your carbs, and you have to pump it a lot to get it going, and it coughs and pukes a few times while it's starting up, then it might cough some gas up onto the inside of the air filters making them stink, especially if you only go a couple of miles or have it just sitting in your yard. I've found that you have to drive/run it for quite a few minutes before all that gas evaporates from the filter and the stink goes away.

If you've checked everywhere for obvious leaks (nothing wet on your finger at connections, that sort of thing) and you don't see gas stains down the side of the carb(s), then try running it for a bit longer and see if it goes away all by itself.

Most of us are used to new cars with fuel injection, computer controlled fuel mixture, etc.

We forget that many carburetted cars do have some gas smell to them. My old sports cars frequently had a smell of gas about them (and oil, and antifreeze, and....)

It is, of course, necessary to check them.

J.

When I first obtained my Speedster, I noticed the same Fuel Smell.

I started to inspect for a "Fuel Leak" but there wasn't any.

What it turned out to be in my case, was Fuel Tank Vent/Overflow Hose. It simply wasn't routed/installed correctly.

I extended the length of the Vent/Overflow Hose and routed the path so it would allow for a "Loop or Trap" to be placed in the Vent/Overflor Hose before it enters the R/F Fender and extends downward inside the R/F Fender behind the R/F Wheel/Suspension.

It only takes a very small amount of fuel to be noticable to the your sense of smell. This may not be a solution to your situation however, it solved mine.

I can "Top Off" my Fuel Tank and there is no Fuel Smell! Before, I could only put about 8 Gal. in the tank or I would Smell Fuel.

Good Luck,

Jack Blake

following along roberts lines----filters etc..often smell of
fuel, people use filters that are too short. have you ever noticed
that on smaller (number of cyl.) eng's atomized fuel flows in and
out of the carb throut at lower rpm's. depending on the velocity
stack area or lack of space in that area fuel can adhere to filter
/housing/cover and if not given time to evaporate/burn will "stink".

Thanks, everyone, for your suggestions. Joe has a family medical emergency and is in Arizona (we live in New Jersey). He'll catch up with these posts when he returns.

Gin P.

You might want to check to be sure your carbs are not leaking gas in the "engine off" condition. Both mine were. Corrosion inside the carb had buggered up the fuel shut-off needle and the choke parts, allowing gas to flow through the carb into the manifold even after the engine was off. In speedsteers, THE GAS TANK IS HIGHER THAN THE CARBS. Can you say gravity flow siphon? I accidently found it by removing the air cleaners and staring down into the carb venturi. Should be dry. It was wet. It stayed wet all day. Finally observed droplets slowly forming inside the carb venturi. Disassembling, cleaning, and polishing the carb parts by my "Weber jeweler" solved the problem. By the way, the excess gas ends up in the oil sump, via an open intake valve. Not good for lubrication.

Another McMaster-Carr find....

For your gas tank vent hose:

Item #7757K42
Polypropylene Spring-Loaded Ball-Check Valve 3/16" Barb X 3/16" Barb
$ 2.90 Each
www.mcmaster.com

Installed mine last night. No more gas smell when making a hard left turn.

Jerome

If it's your sending unit gasket I experienced the same thing after installing a 16 Gal tank, which has more angle where the sending unit is placed. I had fumes from a small leak at one sending unit bolt half way to LA and all the way back. Here's a fix that I just did that works great.(among the others suggested that will work too!):

The #5 Screws holding the unit are hard to tighten.. and even #5 bolts can pull loose if not made of a good quality. So...

I drilled all 5 holes on the sending unit and tank to accept a tap for a #6 (10mm head) hardened bolt. After tapping the tank and using a new gasket, I placed the unit back in, and used #5 rubber washers (worked onto the bolts)covered with #6 copper washers (ie: copper then rubber slid onto the bolt). I brought down the bolts in a pattern of equal pressure ( a torque will do, but I just did it by feel) Then I sinched that baby enough to see the rubber sending unit gasket push out under the edges of the unit... ensuring a good seal. Results? not even a hint of a leak.

As far as venting? I just used the larger fuel line and drilled a hose clip above the cap (height wise) on the firewall and looped the hose through it and out the hole with about 10" drain line below the trunk line clipped to the rear well with a valve in-line below the fire wall clip for slosh. Fuel smells are gone.

I may order another tank and have it coated black then make SS straps that appear to be holding it in. Then run the base carpet around it. Use SS Bolts on the sending unit for a neat look (I hope)

Jim

I've noticed that the venting tube on my IM runs to a very long, thin canister mounted at the back of the trunk, and then runs out of the car. What the heck is this canister thing? Is it some sort of venting/filter canister?
Ron

Ron
Sounds like a charcoal canister that evaporates the gas odor prior to venting it.
...Alan

John at JPS told me to use a Standard DCV-1. I got mine from Advance Auto Parts. Just popped it in the vent hose and done.

BD

You may want to first try tightering the screws that hold the sending unit in place. When I had the same problem with gas fumes with a full tank I checked the sending unit and found 2 loose screws. After tightening the problem went away.

I went to Autozone to get one of these one-way valves, but they could not find that part number or anything matching DVC-1 in their computer. Does anyone have a better part number or know one of the cars that this is a standard part for? I know that I could order one, but I hate to pay more for shipping than the part is worth. Thanks in advance for the help.

Paul

Paul:

First, DON'T go to Autozone - they are absolutely lost if you're asking for something out of the blue that isn't easily found in their computer.

Second, find a local auto parts store that's NOT a chain and has been around for a while and supplies your local garages with their parts. Stop at a good, independent repair garage (drive up in your Speedster) and ask them where they buy their parts from and then go to that store.

Third, you might have gotten the part number letters interchanged. All the independent auto part stores have a Standard Auto Parts catalog, and the p/n given was: Standard DCV-1 (NOT DVC-1 as you typed). Also, the counter-people at the independent auto part stores will understand what you are asking for by your description and can probably find either the Standard part, or help you find an equivalent to it (which the Autozone people can NEVER seem to do).

Good luck!

gn

I think I got my check valve at Advance Auto Parts. (DCV-1)

They can be usually found on the "Help Rack" in "Advance Auto" packaged in red blister packs .