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I've adjusted the carb and timing as suggested and my exhaust still smells very rich. The carb is an Edelbrock 1405 (600 CFM) and I adjusted the thing exactly as the directions state (adjust one set screw for max RPMs, back off slightly, readjust the idle screw, adjust the other side for max RPMs, back off slightly, readjust the idle screw and repeat). I don't want to back off more without knowing what I'm doing, as I don't want to go to far and make it too lean. The exhaust is rich at idle, and with my under-dash vent open I can smell the exhaust even cruising at 60 MPH (I think I have an exhaust leak, but that's beside the point). My gas mileage isn't where it should be (around 12 most of the time), and my guess is the extra gas is passing through unburned (thus the smell). Its not bad enough to produce smoke, but the odor is fairly obnoxious (unless you are just into sniffing gas fumes...each to his own I suppose). From the responses to my earlier post about air passing though my fuel system, it appears I may have the fuel filter in an inopportune place, leading to the fuel boiling. Tomorrow I will relocate the filter to between the fenderwall and pump, instead of between the pump and filter. I had moved it as I was told by someone (can't recall who) that the pump would work better if it pushed fuel through the filter, rather than having to pull it through. Anyway, and ideas on what I need to do? My exhaust tips (GT style through the rear valance) are black with soot :( Thanks for the help :)

'65 289 4V Edelbrock 1405 600CFM C-4 yada yada yada
 

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The exhaust leak is probably causing the smell inside the car. My 66 with a Holley 600 also has a rich smell at the tailpipe tips. I have my carb adjusted as you. Rule of thumb on the mixture screws are to close until the engine starts missing. Then back out, you'll hear the engine smooth out. Then adjust out some more till the engine misses again. Then back in until you've found the middle of the smooth part. Find the exhaust leak, fix it to keep the fumes out of the interior. Then let the people behind you worry about the rich smell at the tips :) Ain't all 60 model cars suppose to have a rich smell? It's called horsepower!

Lancaster, South Carolina
66 Coupe, 302, Auto, 3.25 gears. [color:red]Candyapple Red</font color=red> with White Pearl Stripes. Cragars.
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Keep in mind that you spend very little time at idle. I have the same carb and have adjusted it as the book says. I don't really have an overbearing rich smell, but maybe I'm used to it. Another thing to do is to check your air/fuel ratio at idle. In the past I have gone to my local State "Sniffer" station for a courtesy check. They don't charge for older cars. I have compared their readings to a local shop, and they are fairly accurate. Good luck.

65 FB "J" 302 lots of mods. 94 GT K&N only.
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I've got the same problem...I wish I could figure out something to do about it. It's bad PR for Musclecar enthusiasts.
 

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Discussion Starter #5
It's not that big a deal, I just figure it can't be good for the engine (if nothing else it probably fouls the plugs faster), it wastes gas, and like you said the pollution gives older vehicles a bad rap. It's kind of embarrasing to be sitting in traffic and look in your rearview mirror to see the person behind you coughing from the fumes. I'll just live with it if that's normal :)

'65 289 4V Edelbrock 1405 600CFM C-4 yada yada yada
 

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Discussion Starter #7
The plugs look decent considering 4 mos. use. Darkened slightly, but I've seen worse. The cam, as far as I know, is a standard factory grind (whatever Jasper engines uses in their standard rebuilt 289s). Could a vacuum leak at the intake manifold cause a similar problem?

'65 289 4V Edelbrock 1405 600CFM C-4 yada yada yada
 

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Discussion Starter #9
Gas mileage tends to be around 12 MPG. Sucking on the vacuum advance hose causes the bar under the cap to rotate, so apparently it is working.

'65 289 4V Edelbrock 1405 600CFM C-4 yada yada yada
 

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It smells rich because the cost of gas is getting so high, and you have to be rich to afford filling up! (Sorry, I just couldn't help it)
 
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If the mixture is far too rich, the engine won't idle properly. There will also be greyish smoke coming from the exhaust (not white, not blue).

When the carb gets older it wears. When it's worn you won't be able to tune it as good as you used to. I know, because I have the same kind of problems with a side-draught Zenith-Stromberg carburettor (which has more moving parts than down-draught-type carbs in Mustangs).
 
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