Autolite 4100 secondaries

  • i put ridgid see snake heater hose hole to engine bay. And then i go test drive and follow secondaries what happen when i put gas pedal on the floor.Secondaries only open 1/3 ! What could be wrong?


    i took off new replacement coil and put old yellow top coil. car changed totally after the change.Now feels like i need headrest when i put pedal on the floor.But what happen when secondaries open full (3/3)...


    i go next saturday drive 1/4 mile and would be nice that secondaries working right..

  • If you are running a stock Autolite 4100 Hipo carb it has vacuum secondaries and they open slower when you are going slow or are running lower rpms.

    I'm sure that IF your secondaries are free and you don't have a vacuum leak then they will open on their own by vacuum.

    There is a kit on the market somewhere that makes the secondaries open manually if you want....kinda surprised at that much of a difference in changing the coil.....

  • the secondary springs for a holley carb will interchange. gives a good selection to choose from. i have custom tuned sereral that way over the years.

  • <BLOCKQUOTE id=quote><font size=1 face="Verdana" id=quote>quote:<hr height=1 noshade id=quote>

    the secondary springs for a holley carb will interchange. gives a good selection to choose from.<hr height=1 noshade id=quote></BLOCKQUOTE id=quote></font id=quote><font face="Verdana" size=2 id=quote>


    Great idea! Since I traded my 4.11 gears for 3.50, I thought the secondaries take too long to open with the slower RPM increase. I was going to look into that mechanical conversion but this would be a good alternative.

  • I open secondary and take diaphragm off. is it ok?There come fuel out the secondary box when i open it?!


    Edited by - seisei on 07/19/2011 05:05:37

  • There should be no fuel in that diaphram. It gets a vacuum from the primary venturi and that vacuum opens up the secondary plates from the diaphram arm to the secondary plate shaft. There is a cast-in divider "tube" in the top of the carburetor about 1/4 in dia (6mm) about 2 inches long (50mm) centered between the two secondary venturies that is the source of the vacuum. If that "tube" is broken, no vacuum. That was the problem I had on a 4100 carburetor from a 1961 full size Ford 352CID engine.

    Jim

  • year 2009


    60ft=2,530

    330ft=6,695

    660ft=10,214

    990ft=13,267

    1/4mile=15,867

    83,89mph


    Today


    60ft=2,566

    330ft=6,818

    660ft=10,337

    990ft=13,346

    1/4mile=15,848

    89,48mph


    I change new vacuum diaphragm and now the secondaries open full..I open secondarys today and check if there is fuel inside.

  • I open secondaries diaphragm and there was fuel inside.where the fuel comes here?I open carburetors top and check the fuel float. fuel height is 1" from the top .motor is not used for two days

    • Official Post

    Which side of the secondary diaphragm do you find the fuel? Is is under the outer cover or is it in the well of the carburetor on the inside of the diaphragm?


    -Fred-

    65 Koupe early San Jose Phoenician Yellow 4 speed
    66 GT Koupe Dearborn Blue 4 speed
    66 KGT San Jose fastback pony interior Silver Frost 4 speed
    64 Falcon sedan delivery 289 4 speed
    65 Ranchero 289 4 speed
    66 Corvette roadster 427/425 4 speed

  • <BLOCKQUOTE id=quote><font size=1 face="Verdana" id=quote>quote:<hr height=1 noshade id=quote>

    Outer cover was wet on the down of the cover. What check ball?Where it is?What that ball do?

    <hr height=1 noshade id=quote></BLOCKQUOTE id=quote></font id=quote><font face="Verdana" size=2 id=quote>

    Vacuum passage check ball: "- located in the vacuum passage in the diaphram housing, controls the rate at which the secondary throttle plates are allowed to open."

    You need to invest in a Shop Manual for your car. The one on disc is probably your best choice. I'll make some time later and scan the page from mine manual and send the picture and text to you via e-mail.

    Jim

  • Thank you jwc66k for the pics that you sent. I have check ball in there.Is it possible that fuel comes through the secondary throttle control vacuum tube when I let gas pedal up fast.


    I was test drive and after that shut the engine and open carburetor and check floats.pri and sec are both 26/32...few minutes and i notice that fuel is boiling....after that i open secondary cover and there comes a lot of fuel inside the cover where the spring is.Can this be due to carburetor settings?

    I put new top gasket before test drive..If I do hard acceleration, so I smell fuel..


    I notice that when I screws top back...gasket was wet..


    Edited by - seisei on 07/19/2011 03:50:48


    Edited by - seisei on 07/19/2011 05:07:35

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