Carburetor Problems

[cargeke]

Sorry to keep bothering all of you with my problems, but now I'm having carb issues. My stock '65 Falcon with DSII has an Autolite 1100. I rebuilt it when I got the car, about 4000 miles ago. Now that it's getting cold out, the car won't start. I think it's a fuel vaporization problem as it will start with a shot of ether. The choke does seem to work properly. Is there something I can mess with on the 1100 to improve atomization, or should I get a new carb?

Thanks,
Jim

 

[fordconvert]

The choke should be all the way shut when its cold. Later carbs had a vacuum pull off to open it slightly when the engine started. These carbs just have that little (usually plastic) nut that restricts how far the natural vacuum of the engine pulls it open when it starts. Its not as good a system as the later designs that had a more positive movement but still seems to work.

Does it seem to fire at all but not start? If its that pull off issue you should be able to test that by holding the choke all the way shut with your finger while someone else tries to start it. When its all the way closed it pulls in more fuel which is usually what is needed when its cold since most of it does not make it into vapor and into the cylinder.

 

[JackFish]

It won't start at all, even after you've got it going on the starting fluid?
Does it die? I'm thinking fuel pump.
Do you pump the pedal while starting?

 

[fordconvert]

Good point about pumping the pedal, with EFI being the norm for the last 20 years some people never knew how to start a carb or have forgot.

 

[mugsy]

The 1100 has a specific way to start it. You need to pump the gas pedal once or twice, then hold the pedal down about 1/3 the way down and then turn the key. Teh procedure is in the owner'smanual, you can get copies of one from most Mustang parts places.

 

[ludwig]

Cold start (basically SOP for older carb motors):

1) Push the pedal all the way to the floor ONCE. This sets the choke.

2) Depress the pedal about 1/3 of the way as above.

3) Engage starter.

If no go, then:

4)Flutter your foot on the gas until it starts. This loads the throat with gas from the accelerator pump. Don't do this too much or you will flood it. DO NOT push the pedal all the way to the floor. This will either disengage the choke or flood it completely. Then you have to wait a whole minute or more for the gas to run down.

If you do not have some form of electronic ignition (Pertronix, DuraSpark, DUI, MSD) it will start harder, especially when cold.

 

[cargeke]

Hmm, I'll have to try that 1/3 method. I'm familiar with the need to set the choke. I drove the Fairlane in my signature all through high school with few problems, but that has a new Edelbrock 4bbl.

To elaborate further on my problem: At 40 deg, set the choke, pump the pedal once or twice, and it fires right up. 25-30 deg, set the choke, prime, and it starts with a little more cranking. Less than 25 deg, it rarely starts, regardless of cranking time. Ether helps. Most of the time a shot of ether in the air cleaner and the car starts right up, but I shouldn't really need the ether until it gets really cold (below freezing at least). Sometimes if I prime the car and let it sit for a couple minutes before cranking, it fires right up. It's almost like the fuel needs some time to vaporize.

 

[ludwig]

Maybe you have some kind of moisture contamination in the gas. Make sure your tank is more than half full to minimize the water vapor taken in. You can get a water remover that binds with water/moisture in the gas and gets rid of it through the engine. Could be a spark thing too where there is no fire until it dries out.

Just riffing on a theme here. Don't know for certain.

 

[cargeke]

I tried the 1/3 throttle starting method. It starts easier, but still not when it gets cold. This morning it was about 12 degrees out and it tried to catch a few times, but it was never enough. Ludwig, here in Chicago we get ethanol in our gas all the time, which takes care of the water issue. The starting problems have also happened over a couple of tanks from different stations.

 

[ludwig]

Like a' say: just riffing on a theme.

Hope somebody smart chimes in here.

 

[mugsy]

Sure sounds like the choke plate is not closing all the way. When you say that you set the choke have you physically seen the choke plate closed the entire way? Sorry to ask such a basic question and don't mean to insult you. But if the car starts with ether, then there is plenty of spark to ignite the gas. If definitely sounds like a fuel problem and not a spark problem.

The other way to troubleshoot this is to have a friend try and start the car while the air cleaner is off and you are looking at the carb. That way you can see if something is or isn't happening.

Personally, here in the Midwest, all my carbs got two full pumps of the accelerator pedel when cold. Try it and see if it helps; just make sure you have extra time in case this floods the carb.

 

[cargeke]

Mugsy, I've made sure the choke is closing all the way. The car is so inconsistant, it's driving me crazy. It didn't start yesterday morning, so I tried it when I got home and it fired right up! I swear it just doesn't like to start before the sun comes up. This morning it started really hard, but it started. Took several pumps of the pedal, sit for a minute (This seems to help most of the time), and a lot of cranking. It was also 10 degrees warmer than yesterday morning. My dad suggested I try a different carb or new jets. The jets are about the only thing I didn't replace when I rebuilt the carb. Do the jets make a difference on how the car starts? Where can I get jets for the Autolite 1100? My wife is getting really ticked off at me when I have to take her car or she has to drive me somewhere because mine won't start. I need to lick this problem quickly. Thanks for all the help so far.

 

[66200i6]

The Jets only come into play "Off Idle".

Make sure that the accel’ pump is working when you pump the pedal. Look down the carb and move the linkage. Confirm you are getting that squirt of fuel. Could be a bad accel’ pump.

Good luck, Ric.

 

[addo]

I'd be checking the ignition system fully, too. A weak spark or too much initial advance could make it hard starting in the cold.

 

[jahearne]

Me too!

Me thinks it's condesation under the distributor cap. Try spraying a bit of WD-40 in there. Look for sparks leaking with the car running, hood up in the dark. Might have bad wires too.

Good luck,

 

[jamyers]

Don't mean to beat a dead horse here, but have you watched the choke butterfly while it's cranking? If that spring-tension nut is on the loose side, it can let the choke butterfly bounce open while cranking, killing the choke effectiveness. It can fool you - it closes all the way, but when you button it all up it's not completely working.

I'd check the ignition to be sure it's not an issue, maybe shoot some WD-40 like suggested above, but I'm thinking it's a choke issue in the end.

 

[fordconvert]

 

[70 grabber]

Also dont forget at those temperatures the oil gets really thick and your battery has less amps.I know in north dakota anyway below 30 deg. you start plugging in a block heater or your car sometimes wont start!Could just simply be a combination of low cranking amps heavy oil.If the oil holds it back enouph it will try start and die. just a thought

 

[Rinke]

At work here we've got a similar problem with one of the drilling rigs.

When the temps go down below 0 (celcius) or the air is very moist and cold the machine has a hard time starting, it will crank but not start.
After leaving just the lights on for a few minutes, the thing usually starts.
The theory behind it is that the battery is too cold. Just turning on the lights will activate the battery and cause it to heat up a little. This generates enough amps to start the engine.

Rinke

 

[cargeke]

I've got a brand new, high CCA battery in the car, so I'm pretty sure it's not the battery. I can crank it forever, even in the cold. I'm thinking I might pull the carb off the engine and tinker with it a little bit. I thought I flooded it at work yesterday, so I pulled off the air cleaner to check. The choke was open about 1/8", like the carb kit said it should, but I pushed it completely closed. The car started right up with no ether! Tried the same method again this morning with the same results and it was about 10 degrees this morning. I'm thinking the directions in the carb kit are wrong for the 1100. It was a one-size-fits-several kit. I learned tiny fractions of an inch make a huge difference with ignition points. Maybe the same applies to carburetor chokes too.