Here has been much talk about choke settings, but I'm still missing some answers.

Choke heater:
There is some kind of thermal resistor which gives electricity for the choke heater when engine is cold. In my engine that piece is not working and i've passed that and now choke heater is behind switch, so that I can close heater when engine is warmed up. How have You connected that choke heater?

Choke pulloff:
Is there hole in that diaphragm, Should it leak little?
Should that vacuum pod have to be able to pull choke full open? I had to spread that pull off link to make it work correctly when engine is cold,But now it's not opening choke fully open when it is all way back.
When heater is warmed up choke is fully open, but because heater is not pulling choke butterfly open, only pushing it close when it's not warmed, is it possible that choke butterfly is moving little close (swinging butterfly). I can squeeze pull off pod's link to be sure that it's keeping choke fully open, but then I have to also make choke heater pushing stronger to the close position. And it's already closing flap enough.

And one more. Is there any trick to make choke open faster? Other than manual choke.

I really hope that you get what i'm trying to explain. It was really difficult to type what i'm meaning. Also, i have read all articles and posts concerning choke settings. Setting is not so difficult, but I don't like it when it is closed so long.

Joug

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Sorry, my english is not very good

maybe that what I asked, was written so that it is impossible to understand( because of my english) or questions were stupid. Let me know and i'll delete that post.

Joug

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Sorry, my english is not very good

It may be that you have a different choke mechanism than the ones here in the US. Is this heater connected to the choke flap by a 3mm diameter vertical rod? If so, you can bend the rod (kink it) to adjust when the choke opens and closes.

Is it possible for you to take pictures and post them here? This would make things clearer. I think your English is fine, but it is difficult to explain in words.

Lou

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Home of Slant6-powered fun machines since 1988

Joug,
This past Saturday, my son and I rebuilt his newly acquired Carter BBD
two barrel. We got the kit from O'Reilly Auto Parts for about 14$. It had two sets of instructions, so we chose the one more closely matching his carburetor we got from a '76 Volare. It explains how to make several adjustments, one of which is the choke setting. When I get home this afternoon, I'll scan the instructions and the table of measurements and post it up here for you. I don't know what carburetor you have, but the procedure may be the same for yours.

Jerry

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There's a difference between ignorance and stupidity.
Ignorance is not knowing any better.
Stupidity is knowing, yet doing it anyway.

Joug,
Don't know if this will help answer your question, but here are the pages of instructions for our Carter BBD rebuild kit:

_________________
There's a difference between ignorance and stupidity.
Ignorance is not knowing any better.
Stupidity is knowing, yet doing it anyway.

Thanks Lou and Jerry

And yes Lou, the heater is mounted to the exhaust manifold and connected to the carb with that 3mm rod ( very unusual to find millimeters at this forum ) I also have bended it so that it's not closing very strongly choke valve when engine is cold, but I can't bend it more without having problems with starting.

I didn't think enough. I also have those adjusting instructions (nearly similar than those you scanned Jerry) and it's pretty clearly printed that vacuum diaphragm is not pulling choke full open. So only thing what holds choke fully open , when engine is hot, is weight of the heater rod and the rod at other side of carb(fast idle rod). This is something that I feel little strange and that's why I asked that.

So there is nothing what I can do for the choke to make it open faster. Maybe I'll have to live with it.

Joug

PS. If anyone else than I have troubles with changing many kind of measurements, there is very good and small desktop program Convert.exe at http://www.joshmadison.com/software/ and it's free.

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Sorry, my english is not very good

Joug,

If this heater is mounted in a pocket in the exh manifold, it may be the spring operated type. You can pull this heater unit out of the manifold and loosen the screw running down the axis of the spring and readjust the spring tension. This, I think, will affect the opening rate.

Lou

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Home of Slant6-powered fun machines since 1988

Lou

It is that type of choke but that model is not possible to adjust, there is no screw in spring axis. I changed that choke heater some while ago and it was same thing with the original heater. So only way to do anything was bending rod. I also think that it has same effect if you bend the rod or turn that spring. Spring will open ( or should I say warmup) as slowly both ways. Maybe I' go for the manual choke some day.

BTW Lou, Other topic I asked mixture settings for cruise and idle. You told me that Your O2 sensor reading is 200mv at cruise. Are you driving with carburetor and how steady is that reading at cruise.

Joug

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Sorry, my english is not very good

Joug,

I have only done measurements on my throttle-body EFI Dart with the O2 sensor so far. It is steady if I'm on flat road and steady speed, but otherwise it fluctuates some. With the tunable EFI, I can adjust the ECU to give whatever O2 reading I want at cruise, but 0.2-0.3 gives best mileage.

Lou

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Home of Slant6-powered fun machines since 1988

Thanks Lou

I hope that somebody else, than I, will also try O2 sensor with carburetor, to at see how it acts in other engine. My readins are not steady (even if I drive steadily at highway) and i think that they fluctuate too much. Because of that I will start many new topics asking more dummy questions to make my slant6 work better.

Joug

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Sorry, my english is not very good

If you are getting 0.2V at cruise with +/- 0.1V, then that is just fine. Maybe I'll try an O2 sensor on my '68 Dart before I put the EFI on it.

Lou

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Home of Slant6-powered fun machines since 1988

I agree with you Lou. But it's jumping from 0.05 to 0.7 unless if I adjust carb very lean, Then it's quite steady, but too lean.

When starting with cold engine, mix is rich and steady about 10 minutes (cruising), and then, rapidly , it goes lean. This is somenthing that I don't understand. My thought is that it should go smoothly lean when warming up, but never. Choke is not stuckin. Distributor advanges are not stuckin.

Joug

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Sorry, my english is not very good

Joug-

From your description, it sounds as if you have the same kind of choke setup as the US cars.

After many years of service and adjustments (and "adjustments"), frequently it's no longer possible to get the system to work right. It is a special challenge with the '73 and later setups, which as you noticed do not have a tension adjusting screw.

You should never have to bend the 3mm actuator rod to make the choke work correctly. If you have to bend it, then it is because you do not have the correct spacer between the carburetor and intake manifold. I've never made one of these chokes work by bending the rod, but I've fixed a lot of them by installing UNbent rods!

To answer your question, no, the choke pull-off diaphragm should not leak any air.

Let's review your choke system:

-Choke thermostat. The bimetallic coil spring inside a sheetmetal housing
that sits in a well cast into the intake manifold and has a metal rod
running up to the carburetor. When the coil spring is cold, it pushes the
rod upwards, which pushes the choke to the closed position. As the spring
heats up, it relaxes the tension on the rod. The well in which the choke
stat sits is heated by exhaust gas flow under it.

After years of service and attempts at adjustment, these sometimes stop working right. They can still be had new, and a new unit is the best place to start when the old one isn't working right.

-Choke heater. This is a small electric heating element next to the
bimetallic coil inside the choke stat housing. Its job is to speed-up the
heating of the spring and resultant choke opening when exhaust heat won't
do it fast enough. Included with the choke thermostat when you buy a new one.

-Choke heater control. This is a small box with a wire running from it to
the choke thermostat/heater unit. This unit controls power to the choke heater. If it fails in the "heat on" position, the choke heater will heat up too quickly, permitting the choke to come off too soon. If it fails in the "heat off" position, the choke heater will never heat up, causing the choke to stay on too long.

-Choke pulloff. The round "flying saucer" looking pod at the top of the
carburetor, with a short vacuum hose leading from it to a vacuum port on
the carburetor body. This item responds to engine vacuum to pull the
choke open when the engine fires, and apply tension in the "choke
open" direction to make sure that as the "choke closed" tension in the
choke stat rod relaxes, the choke does come open. It's linked to the
choke lever with a "U" shaped link, the legs of which can be opened or
closed a LITTLE at a time to adjust the amount of pulloff.

The pull-off must be adjusted per factory service manual specifications. Typically the manual gives a drill bit size. You push the choke closed, apply vacuum to the choke pull-off (I use a piece of hose and mouth vacuum...if you can suck air here, the pull-off needs to be replaced). This vacuum will pull the choke partway open, and you must be able to JUST insert the specified drill bit or gauge size between the upper edge of the choke plate and the wall of the carburetor air horn. Squeezing the legs of the "U" bend...gives more pull-off. Spreading the legs of the "U"
bend...gives less pull-off. The factory spec is the place to start...altitude, gasoline, weather and other factors dictate some fudging
and adaptation for local conditions here.

Need more info? Post specific questions.

Thanks Dan

I have both new, choke heater (choke thermostat) and pulloff. I have feeling that pulloff diaphragm is leaking little, but I'll have to check it to be sure. Some GM's pulloffs have small hole in them and that's why I asked if sl6's diaphragm have too.

One thing I'd like to know is, what is correct thickness of carburetor spacer?

Joug

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Sorry, my english is not very good