Air in fuel lines and sputtering at high and now low speeds

[siteunseen]

Turn the lids a quarter turn moving the overflow bungs away. On the rear it's counterclockwise. There's an indentation that gives you the extra wiggle room.

Here's the way I do the hose.

 

[tetert1]

 thank you for these pictures my carburetors are just like these it has a n otch that's in the way when you try to pull floats head. When you change the needles on the float bowls is there there one for the rear and one for of Front... different ones? also can you purchase any that have a greater flow rate? I have blown real hard into new and old needles and hardly any air comes out. so maybe I need to buy one with a greater flow rate

[tetert1]

 tomorrow when I have time I'm going to try the clear hose..thanks 

[siteunseen]

35 minutes ago, tetert1 said:

 thank you for these pictures my carburetors are just like these it has a n otch that's in the way when you try to pull floats head. When you change the needles on the float bowls is there there one for the rear and one for of Front... different ones? also can you purchase any that have a greater flow rate? I have blown real hard into new and old needles and hardly any air comes out. so maybe I need to buy one with a greater flow rate

Yes, the front is longer going deeper in the chambers to account for the gas going towards the windshield when you accelerate.  Note the different length "arms" that hold the pins for the floats.  Front is longer for the longer valve.  You just need new valves, not higher flow valves. 

[tetert1]

 thanks for the pictures that explain the different sizes in the floats. Are there filters in the float bowls you need to change too or check?

[siteunseen]

8 hours ago, tetert1 said:

 thanks for the pictures that explain the different sizes in the floats. Are there filters in the float bowls you need to change too or check?

Yep, they are small barrell filters in the banjo bolts right before the float chambers.  I personally do not use them.  I have two filters before the carbs that do the job.  Those small filters are hard to find new and actually they cause a little restriction of fuel flowing into the carb in my opinion and my opinion was told to me by many folks on here and at Z Therapy. 

    

 Circled in blue in this picture.

Edited December 30, 2019 by siteunseen

[tetert1]

Thanks for the great pictures also the float jet needle that is longer goes to the back carburetors and the short one go to the front carburetors right??

[tetert1]

 also I got a gas can and ran a hose from the mechanical pump to it and still getting air to the carburetors and when I shut the engine off air is coming back towards a gas can so the fuel pump must be sucking air .. ever heard of mechanical fuel pumps doing this?

[Zed Head]

The bubbles could be from gases already in fuel.  Like carbonation in soda.  I wouldn't get too hung up on the bubbles.

Here's an article about vapor bubbles in diesel fuel.  Not gasoline but the principle is the same.

http://www.davco.com/forms/troubleshooting/F1318.pdf

[siteunseen]

Look below the battery box for corroded hard fue lines. Mine had some small pin holes so I cut them out and ran rubbet fuel hose to the pump.

The longer valve goes to the front carb. Think about the fuel level changing going uphill. The front gets low that's why they made them longer/deeper.

That's an old pump from looking on my phone. Your a/c compressor is a Yorx and oh what a pain in the butt to remove the fuel pump. If your air doesn't work I'd throw that SOB in the trash when you have to remove it. They make more efficient smaller units now that use current freon. $1,000 though so I don't have air but a nice spacious engine compartment.

[tetert1]

 I took the back carburetor float out to inspect it by the firewall it has a long needle in it like the pictures you have on the float the one on the left it's the one I had in the rear carburetors by firewall..if you are saying the long valve  goes on the front carb than mine are on wrong.. . is that the right one? yes the AC works a guy just put 13 freon in it with the fittings and it cools good since before summer. . that mechanic said those AC compressors are indestructible hadn't been used since 1981. license plate

Edited December 31, 2019 by tetert1

[siteunseen]

Mine had the longer one on the front carb.

I did some reading and used two rear carb lids on my 72. They are both short and much easier to set the floats level. I have extra carbs and parts so it was a no brainer.

Let me ask my Sensei @Mark Maras to be sure. I could be wrong but I doubt it.