1969 428 CJ carburetor question

[4twennyAint]

What is the function of the gizmo on the top of the front fuel bowl?  The extra lever and rubber grommet...I think it was on 67-69 Holleys, 390 GT, 428 CJ...trying to get the exact, correct SCJ 4spd Torino carb here.  Thanks!

[cammerfe]

It's a vent, with a linkage to seal the hole with the rubber part of the time. Move the throttle and see it operate.

KS

[Tobbemek]

 The mechanism was to vent hot fuel vapor to the atmosphere instead of inside the air cleaner true de regular bowl vent creating a rich condition when started or idling hot soaked . 

[gdaddy01]

I wonder if something like this would work on the flooding Eldie carbs .

[Tobbemek]

I wonder if something like this would work on the flooding Eldie carbs .

The hot carb "flooding"/bad behavior  problem  particularly  with modern fuels hits all type of carbs.
I work/restore on all types of carbs from 50-60-70 mostly OEM and what i see all the times is that carbs with internal float adjustment ( bending tabs )and  the float hanging from top cover, they are high ore very high in fuel level adjustment.
If you toss the top cover on the working bench with floats down there is a big chance you wack the adjustment and get a to high fuel level and with today's high level alcohol fuels, carbs get very sensitive with high fuel bowl levels.

[machoneman]

I'd first try to isolate the carb with a spacer (phenolic/wood, et al) to minimize heat soak. It does seem that 10% alky-laced gasoline is much more prone to heat and overflowing bowls. That and insulating the pump-to-carb fuel line from engine heat. Now, if you are running pure gas (no alcohol) and have good heat isolation then the previous post (float level) looks more suspect.

I wonder if something like this would work on the flooding Eldie carbs .

[gdaddy01]

thanks for the replies , I have the spacers in place and they did help a lot , just not enough in the summer in north west Florida . I think I will set the floats . It would have been nice if elderbrock would have made the duel four intake to accept hollys .

[Tobbemek]

INow, if you are running pure gas (no alcohol) and have good heat isolation then the previous post (float level) looks more suspect.
 
Living in a hot climate, always isolate carbs and fuel lines for heat protection and if possible run a return line to gas tank instead of a dead on circuit.
Running OEM carbs on stock engines  is always more sensitive fore any changing in calibration like fuel levels, changing jets ,rods . power valves ore airbleeds  because they in general are so close in lean factory settings, do to emission paragraphs and mileage than aftermarkets universal carbs that usely  are rich in there calibration to run out of the box in several different combos.  The Carter/Edelbrock carbs type of fuel bowls has hard cornering issues  but besides that lowering the fuel level 1/8" to start with ore  a tad more if necessarily from the correct fuel level settings is wort testing  to overcome a hot percolation situation on a street driven car IF YOU HAVE already gone the insulating route.