What is reasonable to expect from my choke and carb (long)?

[Grover]

Every time I ask a question like this people always ask for more details to help troubleshoot, so I'll err on the side of providing too much info. Sorry, in advance, to those who get bored...

I am running a 38/38 DGAS which has had the water choke removed and an electric one put in its place. I do not know the jetting as I've been initmidated by taking the thing apart, spilling fuel all over the place or taking something apart and no reassembling it correctly.

When starting the car cold in the morning (about 40 degrees this time of year) I depress the accelerator once, then turn the key and it fires right up with no delay. It will not idle on its own at this point, I have to give it gas until the needle is just above the blue mark on the temp indicator. If I do not give it gas it will either stall or shake violently like MC Hammer in "Hammertime." Once fully warm the car idles fine at about 7-800 rpm.

If the car has operated at normal temp for some period and then I park it for all of five minutes I can start it right up with no issues. However, if I leave it for 10 minutes or longer, it will only start if I depress the accelerator pedal all the way to the floor and hold it there while turning the key for 2-3 seconds until it fires up.

Is this an issue with the choke not being set correctly or more likely to be a jet issue? Float problems? Thanks in advance.

[cj]

If I'm not mistaken, you can adjust the choke for higher idle speed at cold start-up. Also, I usually run my idle at 1k when the motor and fluids reach normal operating temp.

Cris

[Grover]

Thanks CJ. Any more details on that idle adjustment? On a seperate note, have you seen how much those '68 and '69 Camaro's have been going for a Barrett Jackson?? Hope all is well with you.

[Beaner7102]

Sounds like you choke is not comming on properly. The water choke on my old solex would idle at about 1200rpm up to 1800rpm before switching off. So you could start it and walk away. Are you getting power to the electric choke? There should be a relay powering the choke, check that too.

I like to set my (warm) idle at 800-900rpm so if you have wipers, H lights and heater fan going the alt light is not on.

Beaner7102

[johnny]

Grover

I have the same set up and my car does exactly as yours here aross the bay. I was just about to post the same question, hopefully someone will have some answers!

[cj]

First off, make sure you're getting 12v at the choke with the ignition on then take a marker and draw a line across the outer choke cover to the carb body. Use this as a starting point. With the motor stone cold, loosen the 3 screws that attach the cover to the carb body. Rotate the cover clockwise until there is approximatly 1/16th of an inch break on the line you marked. Start the motor and see if the cold idle increased. If the idle is too high(2krpm), back off the adjustment. Opposite if still too low. As far as Barret Jackson is concerned, i'm glad to see the nicely restored/modified cars are bringing good money. The other Camaro that I did for my mother-in-law(numbers match SS) will always do well.

Cris

[Grover]

I'm not going to say that it's properly adjusted, but the choke is working to a certain extent since the butterflies will move, they just don't seem to adjust to ambient temperature very well. Please keep those ideas coming.

[Mike Self]

the auto choke versions have essentially the same setup. Besides the choke itself enriching the mixture (by cutting down airflow and thus increasing the gas to air ratio) there is some linkage there that simultaneously increases the idle speed while the choke is on.

The linkage is called the "fast idle cam" and is a serrated or ramped stop that the idle speed adjustment screw hits. The best way to figure it out is to take a look at the carburetor (engine off) while moving the choke linkage. If you manually close the choke (so the choke plates at the top of the carb are closed) you should see a link that leads to the fast idle cam move in concert. That link (at least on the 32/36s) is adjustable, so you can make the engine idle faster while the choke is on. It sounds like that's what you need to do.

cheers

mike

[Grover]

OK. So let's assume I'm able to get the car so it will idle properly after a morning cold start. How SHOULD the car start throughout the day after varying periods of sitting? Should it start just by turning the key? Should I give the accelerator one quick press prior to turning the key to "set" the butterflies in place? Should I have to hold the accelerator down while turning the key until the engine catches? Thanks, I'm just trying to figure out how this thing works when set optimally.

[cj]

On my 32/36, I would depress the gas once when stone cold and crank it. It starts and idles at 1500. After a coulple minutes, blip the throttle and idle comes down to 1k.

Cris

[Guest Anonymous]

wait a minute... mine does the opposite. Mine will start and hold idle at about 1000rpm (sometime very reluctantly), then after 2-5 minutes (just as the temp gauge is getting out of the blue) it automatically (sometimes) kicks up to 1500-1700rpm. I thought too that it was to be the other way around but I have a brand new carb and it has been not acting very consistent. If I turn the high idle screw in it doesn't bring the idle up much more when it's stone cold, but it will make it kick up to a scary 2500-3000rpm which i don't want. I've played with this a lot and I can't seem to dial it in!

SO, what exactly is the proper operation/behavior of the choke?? (mine is the water choke)

[Guest Anonymous]

wait a minute... mine does the opposite. Mine will start and hold idle at about 1000rpm (sometime very reluctantly), then after 2-5 minutes (just as the temp gauge is getting out of the blue) it automatically (sometimes) kicks up to 1500-1700rpm. I thought too that it was to be the other way around but I have a brand new carb and it has been not acting very consistent. If I turn the high idle screw in it doesn't bring the idle up much more when it's stone cold, but it will make it kick up to a scary 2500-3000rpm which i don't want. I've played with this a lot and I can't seem to dial it in!

SO, what exactly is the proper operation/behavior of the choke?? (mine is the water choke)

[Mike Self]

When stone cold, press accelerator pedal once or twice to "set" the choke. This causes the linkage to close the choke butterflies (and incidentally give the engine a squirt or two of gas from the accelerator pump).

When the engine starts, it should immediately idle at about 15-1700 rpm without stalling. Drive off. As the engine warms up, the idle should drop down gradually (you'll notice when you take your foot off the gas) to it's normal 800 or so rpm.

Now here's the divergence: an electric auto choke will turn off faster, as the electric heater causes the choke to go off faster than a water choke. However, when the engine is turned off, the electric choke cools off faster than the water choke, so the car will sit for a shorter time before the choke will be completely off when you re-start (exact time is dependent on how long the engine ran and the outside temp)

The water operated auto choke takes longer to turn off, as the water takes longer to heat, but is slower to cool down to the point where the choke will completely disengage when you go to restart.

That's how it should operate; if yours isn't, it's time to dig out the Weber manual and do some troubleshooting--or just observe the choke action and figure out what it's doing (or not doing) wrong.

happy troubleshooting

mike