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Discussion Starter #1
My better half has been complaining about the gas smell in my '69 Giulia1300 TI (single Solex carb) since the day I got it. Not having as keen a sense of smell, and thinking that a faint gas smell was part of the romance of the Giulia, I've been overlooking it for a while. But lately it seems to be much worse...particularly after filling up...so much so that on a recent grocery run, I got a gasoline headache. If the smell is worse after filling up, does this suggest a problem with the venting system, and if so, what is the remedy?

Any suggestions would be much appreciated.

Cheers,
AA
 

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My father's MGB GT always had a slight fuel smell and like you we just thought it was part of the old car charm. Recently it failed a WOF (NZ safety check) due to rust in the boot floor. A new floor panel was bought and installed by a professional and to do this the fuel tank was removed. While out the fuel tank was stripped for painting and low and behold it had rust holes in it that meant when filled up it would have leaked fuel.

I suggest therefore that you drop your fuel tank and effectively restore your whole fuel system (restore the tank, replace all fuel hoses, pressure test the metal fuel line, replace fuel filter, rebuild mechanical pump if never done before). These cars are old and the best way to ensure a system is correct, is to just check the whole system. Thankfully in regards to the fuel system there is not much to it.
Pete
 

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Some smell is now unavoidable as gasoline has been replaced by "fuel". Todays brew is designed for sealed fuel systems in FI modern cars. It contains many more volatile components than were found in old gasoline for easy starting and smooth idle with FI in all air temperature situations. Beside iso propane and butane there is more to create fumes than with gasoline, and the old Alfa systems are designed as unsealed systems, just like any vehicle that used carburetors. Hot shut down parked in a closed garage will be a smelly situation with todays fuel in older vehicles.
 

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The only "system" aspect of the venting on the tank of a 1300 TI is the vented gas cap. It vents to the atmosphere. You might pull up the trunk mat, see how it looks around the fuel gauge sender, and check all the hoses and pipes from to rear and their connections. Perhaps also a leak the carb? I just sorted a Giulia Spider on which the accel pump diaphragm on the Solex allowed all its gas to run out, down the side of the carb and manifold.
Andrew
 

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Must have a leak for the result to be a head ache.

Hope the source is easily found. My money is on the tank as the boot/trunk is not sealed from the passenger compartment
Best Pete
 

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Discussion Starter #6
An update... I think I discovered the source of the gasoline smell...a gasket in the carburetor (a single Solex 32 PAIA) that was visibly wet, and gets wetter the higher the revs go.

It's the gasket that sits on the top surface of the carb shown
Solex32PAIA1.jpg
Solex3.jpg
in this diagram.
1609111


And again, underlined in white in this photo,
1609112


So, I ordered a net set of gaskets from Centerline, replaced the gasket in question, screwed the carburetor back together nice and tight, fired up the engine, and within a few seconds, the gasket was visibly wet. Not quite as wet as it was before, but still wet to the touch. The strange thing, or at least what seems strange to me, is that the new gasket is a kind of papery material, which looks porous. For this application, shouldn't it be something impermeable?
More broadly, is this model of carburetor just prone to leaks -- a design flaw? -- or do I need to get a different kind/brand of gasket?

Looking forward to hearing your thoughts as always.

Cheers,
AA
 

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That gasket should not have fluid against it (all the time).

Is your float level too high?
Pete
 

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Discussion Starter #8
Thanks for the note, Pete. Does that mean it should never be getting wet, or that the gas should never be up to that height in the carburetor?

Maybe more important, is adjusting the float level relatively easy, or does it require some real technical skills? I'm a little leery of tinkering with the carb's inner workings.

Many thanks,
AA
 

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Your issue is most likely a bad needle and seat causing the float to stick, resulting in the bowl level being too high. dont bother adjusting the float until you replace N & S. Shake the float to see if it has fuel in it and has simply sunk.
 

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Discussion Starter #10
Hi Gordon,

Thanks for the note. It could be that the carb kit I ordered from Centerline comes with a needle and seat. I will check and see. When I had the carb opened up, the float seemed to be floating, but I'll check again.

Thanks for the advice!
 

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Yes on a level road fuel should be below the gasket level.

Gordon is very likely right as your engine ran okay, I believe.

Pete
 

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Discussion Starter #12
Yes, the engine has been running fine, which, because of my general ignorance, let me to believe there couldn't be a problem with the carb's internals.
 

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Discussion Starter #13
It turns out the Centerline kit included a new seat and needle, so I installed it -- a surprisingly painless job. Not surprisingly, fuel is still oozing out from that gasket at higher revs. At idle, there's no ooze, but at 2000-2500 RPM and above, the ooze appears. So this would indicate a problem with the float level, or the float itself, yes?

Thanks again for all your troubleshooting help.

AA
 

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a thought...did you confirm that the float is actually floating? Is it brass or composite? The new fuels are corrosive to brass floats.
 

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I'm not saying there's nothing wrong with your carburetor, but, if the carb were the primary source of the fuel smell, then why would it be worse after a fill-up?

It is probably worthwhile to pursue Andrew's suggestion from post #4 to check the gasket between the fuel sender and tank. And the flex line that attaches to the sender. When one of those parts goes bad, you'll have a fuel leak when the tank is full and get a fuel odor in the cabin.
 

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While there might be other issues, our poster has found an issue and this should be resolved before looking at other areas, or confusion will occur.

So yes, checking the float actually floats makes sense to me. I assume a mechanical fuel pump flows more fuel the faster it is driven, which will cause the leak described IF the float and needle valve do not do their job.

I've always been a fan of a return line to the fuel tank, as it makes life easier on the carb(s) needle valves as the pressure is limited by the size of the return line. But my GTV doesn't have one, although my Sud did, so if shouldn't be required AND we should not modify while the cause of the current issue has not been found.
Pete
 

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Discussion Starter #17
a thought...did you confirm that the float is actually floating? Is it brass or composite? The new fuels are corrosive to brass floats.
It looks like plastic to me. And it floats, at least somewhat. I haven't taken it out to check if there's gas in it though. That's the next step...
 

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Discussion Starter #18
The plot thickens. I took at look at the float today...and...it's totally intact. No evident cracks or pinholes, and no gas sloshing around inside. So that's one possibility eliminated. Given how robust the brass float arm is, it seems unlikely that it would have drooped or bent over time, i.e. gotten out of adjustment, so I'm wondering if maybe it's a case of someone having replaced the original, circa 1969 float with another float that wasn't quite right. My float is stamped 7.2Gy, or possibly 7.26y. Does anyone know offhand if that's the correct part number for a float for a C32 PAIA 7 carb?
 

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Nick
Yes, a 7.2 gram float is correct for your C32 PAIA 7 SOLEX carb .. and Yes, I have them available.
Do not bend the float arm .. the fuel level in the reservoir is adjusted by shim washers at the needle valve body.
Adding washers lowers the fuel level.
Fuel pump discharge pressure should not exceed 4 psi .. check that before modifying anything.
 

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Discussion Starter #20
Hi,

Thanks so much for the note. So the adjustment is at the needle valve. Interesting. And I'd read something in the Giulia shop manual, or was it in the Solex repair manual, that said overflows could be caused by a mismatch between the fuel pressure and the needle valve opening. My current needle valve is a 1.5. Interestingly, the replacement needle and seat from Centerline is stamped 1.75. I imagine even something as small as an additional .25 (mm?) could make a big difference. On the fuel pressure front, what kind of tool does one use to measure the fuel pump pressure?

Cheers!
AA
 
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