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Item Posts    Sort Order

Autolite 4100 settings?

 
lukestang
New User
Posts: 1
Joined: 11/13
Posted: 11/18/13 10:17 AM

I have an all original 65 289 with an autolite 4100 4 barrel on it and when the car is cold it starts right up but once it is hot it will fight to start and the only way to get it to start it to take off the air cleaner and hold open the butterfly flap so my question is how should the RICH <> LEAN black knob on the passenger side of the carb be set or aprox how far should I turn it to have the butterfly flap open to help it start when warm? if anyone could show any pics of how far theirs is set at and how far the flap is open at hat setting  I would really appreciate it! Thank All  

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cushman350
Enthusiast
Posts: 635
Joined: 07/06
Posted: 11/18/13 04:56 PM

With the engine at normal operating temp. and throttle butterflies open, the choke should be full wide open with no more force than necessary. This point is found by turning the black cap one way then the other. Then with cold and throttle depressed, the choke should be shut. If linkage is dirty or gummy, things will not function well. Sounds like its bleeding fuel when hot and flooding, hence the need to hold the blades full open to start. Some old carbs had slot on the spring inside the black cap that had to engage the linkage just so, or the adjustment would fail, but I'm not sure about the autolite 4100 choke. Just have to look inside and pay close attention to what's inside and where.  

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wayne712222
User
Posts: 105
Joined: 10/13
Posted: 11/18/13 10:41 PM

just to help... do you have a choke hot air tube hooked up?? to the exhaust manifold.  so the suction thru the choke housing and the choke thermostat opens and releases closing force on the choke blade to stop from flooding the engine after warm up.  the tube going into the choke housing should be hot enough to smoke your fingers... use care..

166038123

there are replacement choke stove kits as are exact replacements from various vendors..

Help/Choke Stove and Heater Tube Repair Kit Part Number: 55111





CHOKE PLATE CLEARANCE AND FAST IDLE CAM

   Remove the air cleaner and the choke thermostatic spring housing.
   
   Bend a wire gauge of 0.036 diameter at a 90° angle approximately 1 / 8 inch from one end.
   
   Block the throttle about halfway open and make certain that the fast idle cam does not contact the fast idle adjusting screw. Insert the bent end of the wire gauge between the lower edge of the piston slot and the upper edge of the righthand slot in the choke housing.
   
   Pull the choke piston lever counterclockwise until the gauge is snug in the piston slot. Hold the wire gauge in place by exerting light pressure on the choke piston lever. Check the clearance between the lower edge of the choke plate and the air horn wall. To obtain the proper clearance, turn the choke plate clevis adjusting nut as required.
   
   Install the gasket and thermostatic spring housing on the choke housing. Install the retainer.
   
   Rotate the spring housing counterclockwise (rich direction) to align the center index mark on the choke housing with the index mark on the spring housing.
   
   Rotate the spring housing an additional 90° counterclockwise and tighten the retaining screws. Check the clearance between the front of the choke plate and the air horn wall. If adjustment is required, turn the fast idle cam lever adjusting screw inward to increase the clearance, or outward to decrease it. Be certain that the adjustment is made with the fast idle screw at the index mark of the fast idle cam.
   
   Position the fast idle screw on the second step of the fast idle cam.
   
   Set the thermostatic choke housing to the specified index mark and tighten the retaining screws.
   
   If these adjustments were performed while the carburetor was installed on the car, perform an idle speed and fuel mixture adjustment. If so equipped, adjust the antistall dashpot.  

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shyrgfuh1
New User
Posts: 2
Joined: 11/13
Posted: 11/19/13 04:28 AM

i set the butterflies so they are open 1/8 at around 60 degrees and if its 75 and you dont get to 60 then around 2/3. as soon as the car starts the choke will open about 1/4 more.

I would also open and close the choke by hand when it is cold and hot. if it feels sticky at all then the brass choke piston is seizing up in the bore in which case i remove it and sand it with 320 and water or wd40 then grease it lightly and reinstall. i haVE HAD TO DO THIS MANY TIMES BECAUSE THE CHOKE BORES WARP FROM HEAT AFTER SO MANY MILES OF RUNNING but it is easier to sand the piston then the choke bore unless you remove the carb.....if it moves freely it might be that your choke cover is installed incorrectly or the spring is broken...the spring end goes between the slot in the choke arm however if your butterfly has spring resistance in both directions when engine is cold id is ok.

also make sure heat tube is working as shown below.  

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lukestang
New User
Posts: 3
Joined: 11/13
Posted: 11/19/13 11:35 AM

So from what u have all said I am assuming that my issue is simply that I rebuilt the carb and installed it with the butterflies completely closed so I opened it oprox 1/4 of the way and I will see how that works. If anyone could show a picture from the top of their carb so I can see where they have their butterflies set when cold I would appreciate it.
Thanks again!  

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jlg2002
Guru
Posts: 1410
Joined: 03/08
Posted: 11/20/13 02:23 PM

Luke,
The choke butterfly is supposed to be fully closed when set in the cold position. from there when the engine cranks it pulls the choke open about 1/8 inch or so which allows the engine the airflow to start and run. typically when you install the choke cap has an index mark on it that aligns with a mark on the housing. Try setting the cap by rotating it CW until the butterfly is fully open and then reverse direction (CCW) until you get the index mark centered then go 1 or 2 marks more. stop and tighten it down. make sure the heat tube is connected to the carb and the manifold.  this should fix your hot idle problem.  

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lukestang
New User
Posts: 3
Joined: 11/13
Posted: 11/22/13 09:45 AM

Yeah so I tried just opening the butterflies a little and it wont start when its cold and I put it back to fully closed and everything seems to be working correctly when cold but when the motor is warm it wont start if I allow it to sit for any time longer than 5mins or so I can shut it down and then turn the key to start again immediatly and its fine and starts right up but if it sits warm then I try it just fights to start or floods out and the only way to start it is to hold the butterfly open so it can breath so if anyone knows any other tricks please let me know at this point ive tried everything aleady posted and am having no luck.  

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lukestang
New User
Posts: 3
Joined: 11/13
Posted: 11/22/13 09:45 AM

Yeah so I tried just opening the butterflies a little and it wont start when its cold and I put it back to fully closed and everything seems to be working correctly when cold but when the motor is warm it wont start if I allow it to sit for any time longer than 5mins or so I can shut it down and then turn the key to start again immediatly and its fine and starts right up but if it sits warm then I try it just fights to start or floods out and the only way to start it is to hold the butterfly open so it can breath so if anyone knows any other tricks please let me know at this point ive tried everything aleady posted and am having no luck.  

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wayne712222
User
Posts: 105
Joined: 10/13
Posted: 11/22/13 06:27 PM

use a mirror...  as soon as you shut down the engine.. do you get fuel dribble out of the booster legs...

or is your power valve loosely screwed in... or is the power valve diaphragm blown out and allowing the fuel bowl to drain into the intake manifold causing the flooding and the warm start flooding issues.

if its trickling over the various parts of the carb.. or down into the carb via drips off the end of the boosters...  you might have sediment issues..  and need a better fuel fuel filter just before the pump to keep the pump check valves and the carb needles and seats clean and free of sediment.
i normally use  a mid 90s ford fuel filter in the middle of a loop from the fuel line to the fuel pump ..

i have been known to use  a pair of long nose pliers.. get the engine started.. once this filter is installed properly.. and i pinch off the fuel hose coming into the fuel pump.. raising the idle speed to around 2000 RPMs..  when the engine starts to run out of fuel.. i release the pliers before the engine can die..  this allows a big surge thru the fuel pump and the WIDE OPEN needle and seat.. flushing any sediment out..

if you have the sending unit out.. drop a magnet into the bottom of the tank...

if you have a big dead speakers.. knock the magnet off the housing and stick it to the bottom of the fuel tank.. this will attract most of the rust and metal particles to the magnetic field and keep it out of the fuel pump check valves and carb needle and set ..


use a bright flashlight.. and look down thru the carb into the intake... is there a puddle of gasoline in the manifold????  

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shyrgfuh3
New User
Posts: 24
Joined: 11/13
Posted: 11/30/13 07:21 AM

how cold is it when you are starting it. i told you how to adjust the choke butterfly in my previous post.

is it fully open after 4 minutes or less. if not it may need repair.

you can not start a warm eng with the butterfly closed more than around 1/2 way.  

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