Autolite 1100 flooding

[sparky65]

I have issues with the carb flooding when I try to start the car and I am wondering if I need to adjust the float or if its my starting method. Last time I whent to start I pressed and released the peddle once to set the auto choke. Then I cranked it. It cranked for a while and didn't fire. Let it sit for a few seconds and cranked again. It almost fired once or twice then quite. I cranked it and it did the same so the next time I tried to give it a little gas while cranking. But I couldn't get it work. I got out to look and there was a pool of gas sitting on the head that obviously overflowed out of the carb. I cleaned it off let it sit and tried starting it later and I got it to run but it would only idle with the choke on.

THe carb flooding when I try to start it is nothing new with this carb since I had it rebuilt. But it used to run ok, two weeks ago when i started it for the first time this year it ran fine and didnt flood so I dont know what happened now. I just don't want to open it up and adjust the float if the flooding issues are the result of how I start the car.

 

[ludwig]

Your start procedure is correct. Is it hot or cold start? If cold start, it may be that the butterfly is closing all the way and not allowing air to enter the carb. This is essential for combustion.

The repair manual shows that it needs about 1/8" opening on cold start. Adjust the black plastic cap on the side, after you have set the choke, so that you have the required opening. They always show the adjustment using a drill bit as a feeler gauge. Loosen the three screws on the cap and twist it clockwise (I think) to reduce the spring pressure. At all odds, turn it until it stops with an opening of 1/8" when dead cold.

It is possible that the pull off spring is not engaged on the pegs inside the cap or that the spring is reversed and is pressing the butterfly shut instead of opening it. However, check the butterfly adjustment first.

The problem is that once you start the engine, you no longer have a cold start. So you have to let it go dead cold again if that is what you are testing or adjusting.

 

[292fan]

I am having the same problem on my 63 Autolite 1100 with a manual choke. Sometimes I have to tap the carb to get the flow to stop. Once warm all is well. I think when cold the float drops too far and the needle valve gets stuck open. Don't have any ideas to fix yet.

 

[bubba22349]

292fan wrote: Sometimes I have to tap the carb to get the flow to stop. Once warm all is well. I think when cold the float drops too far and the needle valve gets stuck open. Don't have any ideas to fix yet.

A good cleaning, a fresh rebuild kit, and setting the float level and the float drop to the factory specs, would likely fix that one (many forget to set this drop spec when rebuilding on some carbs it can cause sticking if the drop is very low). It's could also be that the float's hinge point is maybe gummed up with varnish too.

 

[bubba22349]

sparky65 wrote: THe carb flooding when I try to start it is nothing new with this carb since I had it rebuilt. But it used to run ok, two weeks ago when i started it for the first time this year it ran fine and didnt flood so I dont know what happened now. I just don't want to open it up and adjust the float if the flooding issues are the result of how I start the car.

Letting a car sit a long time without use and there's a 50 / 50 chance the carb will get gummed up with the fuels we have today sometimes they will clean themselves over time if you can get it to run good enough to use. But did you or whoever rebuilt the carb check that the float was still good? A bad float is also another common cause for flooding problems. Good luck

 

[ludwig]

Ditto to Bubba. If you have a brass bulb float, it could have gotten filled through a pinhole and sunk. If you have a plastic foam float, the alcohol solvents in the gasoline may have melted it. That is a problem these days with ethanol blended gas. You want a metal float with no holes in it.

 

[292fan]

bubba, thanks for the drop check on the float. I never even considered there being one and I will definitely check the manual for that. It all makes sense now.

Thanks again,
292fan

 

[bubba22349]

Yes it's not so much that the drop has to be so exact like the float level height but if it's too low it's kind like it over centers and than doesn't move (rise) right or as easy as it should when float bowl is dry or a very low fuel level. Good luck

 

[292fan]

Bubba, sorry to be a PITA but do you care to guide me through the drop check/adjustment? I don't seem to find that measurement in the service manual. It is a 63 Falcon, 170 ci, F2M, manual choke. :help: Thanks for your time if you can :thanks:

292fan

 

[bubba22349]

No problem I don't have my manuals handy but will see if can get that for you latter tonight. Roughly if it's about 15 to 22 1/2 degrees below level and it should work OK.

 

[292fan]

Bubba, 'preciate your help.

292fan

 

[sparky65]

Your start procedure is correct. Is it hot or cold start? If cold start, it may be that the butterfly is closing all the way and not allowing air to enter the carb. This is essential for combustion.

The repair manual shows that it needs about 1/8" opening on cold start. Adjust the black plastic cap on the side, after you have set the choke, so that you have the required opening. They always show the adjustment using a drill bit as a feeler gauge. Loosen the three screws on the cap and twist it clockwise (I think) to reduce the spring pressure. At all odds, turn it until it stops with an opening of 1/8" when dead cold.

It is possible that the pull off spring is not engaged on the pegs inside the cap or that the spring is reversed and is pressing the butterfly shut instead of opening it. However, check the butterfly adjustment first.

The problem is that once you start the engine, you no longer have a cold start. So you have to let it go dead cold again if that is what you are testing or adjusting.

Yes the problem is during cold start. I'll check the butterfly gap tomorrow but I am quite sure I checked that when we installed the carb but it doesnt hurt to check again. I have had issues since day one with the choke not coming off when the car warms up. Seems like the bi-metel spring is getting hung up, if you push it off of choke manually it corrects itself. Are new choke parts available anywhere?

sparky65 wrote: THe carb flooding when I try to start it is nothing new with this carb since I had it rebuilt. But it used to run ok, two weeks ago when i started it for the first time this year it ran fine and didnt flood so I dont know what happened now. I just don't want to open it up and adjust the float if the flooding issues are the result of how I start the car.

Letting a car sit a long time without use and there's a 50 / 50 chance the carb will get gummed up with the fuels we have today sometimes they will clean themselves over time if you can get it to run good enough to use. But did you or whoever rebuilt the carb check that the float was still good? A bad float is also another common cause for flooding problems. Good luck

The car set for about 4 or 5 months but I always treat the fuel with stabil (triple dose) before putting it in the car. Also the place I get my fuel doesn't have a sign saying 10% ethenol. Of course I cant be sure they comply with the requirement to post the sign but I try not to get ethenol. I also cant be sure he checked the float but he is a reputable carb re-builder so I think he would have. The only issue was the box he returned it to me in was beat to a pulp by UPS so something could have gotten screwed up.

If the float did sink would I ever get it started? wouldn't it spill fuel all over every time I when to start it?

I guess I'll try playing with the choke first since that's the easiest. If that doesn't work I'll open it up and check the float.

 

[bubba22349]

292fan, well appears there is no listing for the float drop spec in my old service station manual, everything else but that. I don't know if it's listed in a carb kit specs don't have one handy. If you have it apart you could feel if its sticking by lifting with a tooth pick or small screwdriver etc. (use a very light touch) or better still by pulling the Float and than by turning the hinge pin it should move very easy if not you will need to clean it with spay carb cleaner, a small wire brush, or some 600 wet & dry sandpaper. The rest of the Float settings for a 1963 Autolite (C3 tags or numbers):

Float level for all C3 Autolite carbs is 1" except for the C3OF-9510-AM it's 1 3/32 inches with a metal float or 1" with rubber float + or - 1/32. Also a C3OZ-9510-E carb is set to 15/16 inch. Have the other setting specs too if you need them. Hope that is of some help, Good luck

 

[bubba22349]

sparky65,

The car set for about 4 or 5 months but I always treat the fuel with stabil (triple dose) before putting it in the car. Also the place I get my fuel doesn't have a sign saying 10% ethenol. Of course I cant be sure they comply with the requirement to post the sign but I try not to get ethenol. I also cant be sure he checked the float but he is a reputable carb re-builder so I think he would have. The only issue was the box he returned it to me in was beat to a pulp by UPS so something could have gotten screwed up.

Okay by what you have said and done above than, think your probably right to mainly focus on the choke adjustment first. I have the specs for that if you need them.

I'll check the butterfly gap tomorrow but I am quite sure I checked that when we installed the carb but it doesnt hurt to check again. I have had issues since day one with the choke not coming off when the car warms up. Seems like the bi-metel spring is getting hung up, if you push it off of choke manually it corrects itself. Are new choke parts available anywhere?

You can get new choke parts like the cover and spring, try NAPA or the Dorman Help parts section of most auto parts stores.

 

[292fan]

bubba22349, thanks again for the info. I will be taking the carb apart in the near future and will check to see if I can adjust the drop and to check the float level height. I know it's gotta be something simple as it doesn't do this every time on the first start of the day. :thanks:
292fan

 

[bubba22349]

OK, yeah by your description of the problem I believe that your right and it should be easily fixed. Good luck

 

[sparky65]

Okay so I played with it some today. First I depressed the pedal like I was going to start it and then I got out and looked at the choke. It was closed but still probably open 1/2". Now that I think about it does the choke close the same distance every time or is it based on temperature? It was about 60F this morning when I tried it. Anyway I figured it was wrong so I ran through the whole procedure of first setting the throttle plate opening and then the choke. In the process of backing off the choke idle screw I realized I could move the choke cam further by hand almost as if it got stuck or the spring isn't strong enough. Also the cam the screw rides on doesn't seem smooth so maybe that is related. Anyway I finished up the adjustment and went to start it. It started no problem without flooding. No idea what the real issue was though.
Two other things I noticed that somewhere along the line after it ran for a while a little fuel came out of the fuel vent by the plastic arm. Also I played with the mixture screw some. Really didn't seem to make a difference. I expected it would effect engine rpm as I leaned out or made the mixture to rich. Definitely as I screwed it in it started to stumble but I had it almost all the way out without a change. As set Its like 6 or 8 turns out, does this sound right? The reason i played with the mixture screw was because after the choke was off on acceleration it has a spot where if you just give it a small amount of gas it would stumble or stall. If you hit it a little harder it will plow through no problem. There is just a small area where it is a problem. I think I might look at the timing for that problem unless you think this could still be related to the flooding.

 

[bubba22349]

Wow think you will need to start over and not make so many changes at once. Fuel coming out the vent means the float is too high or is sticking, or the float is too heavy, that needs to be fixed first. You are working with a 1967 carb right? Do you know the carb number that would help also is it an auto trans or stick? If its a 1964 to 67 Autolite than set the Float level too 1 3/32 inches with a nitro float or 1 inch + or - 1/32 with a brass. The idle mixture screws will have very little to do a flat spot or stumble on acceleration set them to 1 1/2 turns out to start with than refer to the lower tune up tips.

Now that I think about it does the choke close the same distance every time or is it based on temperature?

The choke blade needs to be set when screw is setting on the right fast idle cam step with the cover set to the correct index position this can be from Index to 2 Lean depends on which carb number. Fast idle RPM with choke set is 1400 to 1500. Accelerator Pump setting is .190 to .210 depends on carb number.

Order of making Tune up adjustments for the best results
1.Gap and install plugs
2.If you still have points set the gap or use a dwell meter for even better results
3.Set the timing.
4.With engine warmed up good set the curb idle 500 to 700 RPM depends on the trans Auto is set in drive with emer. brake set.
5.Set idle mixture for best idle RPM. It may be necessary to repeat #4 and #5 two to three times to arrive at the right settings.

 

[sparky65]

its a 67 carb, auto trans, 6d0-AC or something like that.

The choke blade needs to be set when screw is setting on the right fast idle cam step with the cover set to the correct index position this can be from Index to 2 Lean depends on which carb number

I don't know how the cover index was set but the manual didn't say anything about that it just said to close the choke on the gage. So If I understand it right the position of where the screw stops on the cam has to do with how the position of the cover?

 

[bubba22349]

OK here you go Good luck. Carb is a C6OF-9510-AC
Adjustment Specs are:

Idle RPM = 500 (warmed up) trans in drive
Fast idle RPM = 1500 (choke is on)
Float Level setting = 1 1/32 inch stock is Nitro type Float
Throttle Valve = .020" inch

Accelerator Pump setting is .190" inch

Auto Choke cover (Black spring Cover) = set to Index mark
Choke Pull down settings
Choke valve = .140" - .160" inch

These settings are made with the carb off the engine

With carb top turned over so float is facing upward, no extra pressure other that gravity and weight of the float on the needle and seat. Measurement is 1 3/32 inch with the stock nitro type float. If float has been changed over to a brass one than set it at 1 inch + or - 1 /32 inch. Measure from the gasket flange of carb top to top front edge in the center of float with your scale or a machinist ruler etc. If you have to adjust the measurement carefully bend tab to adjust height, for sure don't plush down on float assembly when installed it will cause damage to the needle and not work correctly.

Lightly bottom the Mixture screws and than turn them out 1 1/2 turns.

Accelerator Pump Setting

Make certain the roll pin is set in lower HI position in pump lever with throttle valve completely closed. Insert gauge or drill bit of the correct size (.190" inch) between the roll pin and pump cover surface. Bend pump rod to obtain correct clearance. Seasonal setting for temps below 50 degrees install roll pin in Hi (lower hole of pump lever) for temps above 50 degrees or altitudes above 5000 feet install roll pin in low (upper) hole of the pump lever. If you have a bowl vent valve after the pump setting is done and linkage in the hot idle position grove in bowl vent valve rod should be even with edge of vent valve housing. Adjust by bending arm on vent valve operating lever where it contacts the accelerator pump lever.

Choke Valve pull down

Remove the choke cover and spring block the Throttle valve half open so that fast idle screw dose not contact the cam. Bend a .036" inch wire (a paper clip will work) at a 90 degree angle 1/8 inch from end. insert the 1/8 end into the lower edge of the choke piston slot and the upper edge of right hand slot in choke housing. Move piston lever counter clockwise until the gauge is snug in slot and lightly put pressure to hold it there, insert correct gauge or drill bit (.140" - .160" inch) between chock blade and air horn wall. Carefully bend choke piston link rod until clearance is right. Next install choke spring cover with gasket turn to index mark on cover and choke housing turn additional 90 degree counter clockwise (rich) and tighten the cover locking screws.Position the fast idle screw on index mark of fast idle cam. Check the choke valve clearance with the same gauge as the pull down adjustment above (.140" - .160" inch) If necessary adjust by bending choke connector rod for correct clearance. Loosen the coke cover screws and reset to the choke cover index mark to choke housing index mark and your ready to install carb.

With the Carb installed settings

Idell mixture for the standard engine (IE Without the Thermactor system) Starting with screws 1 1/2 turns out than Engine is warmed to normal operating Temp. Adjust mixture in leaning it out until engine RPM begins to drop. Than turn mixture screw out until RPM increases and begins to drop from a too rich mix. Finally turn screw in until you have the max RPM and smooth idling Recheck ans or set the curb idle speed to spec (500 in D). Next adjust the fast idle speed to spec by manually rotate fast idle can so the fast idle adjusting screw is aligned with the reference mark on the cam and adjacent to shoulder of the highest step on cam. Engine warmed up to norm temp adjust fast idle screw to RPM spec (1500)