Slant Six Forum
https://slantsix.org/forum/

Cold weather starting issues
https://slantsix.org/forum/viewtopic.php?t=42890		 Page 2 of 3
Author:  Reed [ Thu Dec 16, 2010 3:10 pm ]
Post subject: 
Yep, the Carbs Only kits come with the "thermistor." I just got one last week for my brother's van. It is a two barrel version, but it had the thermistor with the kit.
Author:  scottdart [ Thu Dec 16, 2010 5:00 pm ]
Post subject: 
Ok here's my update. First a big THANKS for everyone who chimed in with some great tips, very helpful and it learned me a little too :P

Utilizing your info I as able to get a pretty good adjustment to the "U" shape in the pull off linkage and I now have the choke flap/plate staying nearly closed upon cranking (in the 1/8 to 3/16's area). After getting this set the car started up and stayed running the way it should. I tapped on the gas after a few secs and kicked down the fast idle one step w/ no problems.

The only issue I have now is the fast idle is staying on that first step ( not the highest, but the next one down, but still to fast) I let the engine get pretty warm but I still couldn't get it to drop another step into a good low (curb) idle. As you may guess by now I'm not sure how to remedy this issue yet. But at least with your help I have the choke apparently set alright! Thanks again Everyone ..now just need to get that idle doing right.
Author:  Reed [ Thu Dec 16, 2010 5:06 pm ]
Post subject: 
Yay!

To answer your earlier concern about the inner and outer plungers on the choke diaphragm:

(These are on a different carb, but the principle is the same)

(1) No vacuum applied to diaphragm. both pistons are extended:

Image

(2) vacuum applied to diaphragm, both pistons retracted:

Image

(3) Vacuum applied to diaphragm, light closing pressure applied to choke plate. Inner piston retracted, outer piston extended but limited by inner piston:

Image


Picture 3 illustrates why you need to have vacuum applied and light closing pressure on the choke when yo adjust the choke pulloff linkage.



Now that you have the choke linkage adjusted near correct, you need to adjust the fast idle linkage. On the side of the carb with the fast idle cam there is another linkage piece with a u bend that you use to adjust it. It sounds like you need to open this U up as well to allow the fast idle cam to drop past the fast idle screw once the carb is warm. The manual I linked to above will give you instructions on how to do this.
Author:  Reed [ Thu Dec 16, 2010 5:08 pm ]
Post subject: 
This might help:

Image
Author:  scottdart [ Thu Dec 16, 2010 7:53 pm ]
Post subject: 
Quote:
Now that you have the choke linkage adjusted near correct, you need to adjust the fast idle linkage. On the side of the carb with the fast idle cam there is another linkage piece with a u bend that you use to adjust it. It sounds like you need to open this U up as well to allow the fast idle cam to drop past the fast idle screw once the carb is warm. The manual I linked to above will give you instructions on how to do this.
Before I try another adjustment I want to be sure that I'm looking at the right linkage piece that is the fast idle linkage. Here are some more pics showing what I think is the right thing, however I'm a bit unsure because I can't see a definitive "U" shape as much. Although it does sort of have one near where it attaches at the bottom ( the inside photo of the linkage shows what I'm saying). I just want to be sure I'm looking at the right linkage piece.
<img src="http://farm6.static.flickr.com/5163/5267919306_5dd8771b1f_z.jpg" width="640" height="480" alt="Outside of linkage" />
<img src="http://farm6.static.flickr.com/5246/5267919212_358880f683_z.jpg" width="640" height="503" alt="Inside of linkage" />


Assuming this is the right link where would I make the bend? Does the car need to be running warm and in neutral for this? Do I need the car off, cold w/ throttle manually pull back and resting on the highest step of the cam? I'm reading allot about idle adjustments and I'm reading about turning screws, bending rods, etc.. It's confusing me ..Sorry for being troublsome.
Author:  Reed [ Thu Dec 16, 2010 8:09 pm ]
Post subject: 
No problem. It takes a while to learn all this stuff.

You have identified the correct rod to bend. You can bend the large flat "V" area, or the U area you found. The U would probably be better.

You can make the adjustment by holding the choke all the way open with your hand and then opening and closing the throttle to see where the fast idle cam falls. The motor can be off and cold.
Author:  scottdart [ Thu Dec 16, 2010 9:36 pm ]
Post subject: 
Ok I'll try to do this by this weekend sometime. Hopefully it will all work out because this car is my only means of transportation, and I go back to work on Monday. I probably could drive it as is, but I think with it idling so high, it would slam into drive and be murder on my mileage too. I'll let you know how it goes.

It's good to know that I have a place where my silly questions can be answered. Thanks
Author:  Reed [ Thu Dec 16, 2010 10:07 pm ]
Post subject: 
Don't worry. We have all been where you were. I was fortunate enough to encounter some very knowledgable and helpful people who helped me as I learned how to work on cars, so I am happy to share what I have learned with others.

You can also just disconnect the rod going to the Carbs Only choke coil to let the choke flop open and the fast idle cam drop as far as it will go. This whole adjustment should take under 5 minutes.

You might need to adjust the tension on the Carbs Only choke coil to get it to open as quickly or as slowly as you would like.
Author:  wjajr [ Fri Dec 17, 2010 7:01 am ]
Post subject: 
Ted:
[quote]I thought that the electric chokes from SL6Dan's link came with one. I read where guys were trying to figure out where to mount them...........[/quote]

Ted I did not know that a thermister is included with the electric choke conversion, which is very good, as I have never seen one in person. I have my Holley thermister mounted with a bolt in the rear boss top of the head where one would attach a chain to pull the engine. Knowing about a thermister may help others that suffer poor electric choke performance.

Bill

Thermister is small black box at tip of pencil:
I made a little bracket to mount it to the head from a straight strap that one can find at a hardware store next to the “Lâ€￾ brackets.

[img]http://i294.photobucket.com/albums/mm87/wjajr/Dart%20Engine/100_1340.jpg[/img]
Author:  wjajr [ Fri Dec 17, 2010 7:39 am ]
Post subject: 
Scotdart,

Miscellaneous ramblings of an old fart:
Working on a choke for me is very intuitive probably because I’m old school, and trust my eye to see how something mechanical works. Plus growing up, I was fascinated by Rub Goldberg’s [url=http://en.wikipedia.org/wiki/Rube_Goldberg_machine] machines[/url]…

Adjusting something with a laptop as the new kids on the automotive block do these days just ain’t the same in my book…

You will have to fiddle around a bit more in order to fine tune your choke. Be patient, you are real close to perfection. The more you play with it the easer dialing in one of these devices will become. With a cold engine, set and work the mechanism over & over until your eye can catch all the action, and see where and what is causing the maladjustment.

Practical tip to newbie “Choke Mr. Fix-itsâ€￾:
Whatever you do, do not lubricate any of the carburetor’s linkages in the misguided attempt to get something to move more easily. All it gets you is gummed up moving parts a few weeks down the road from dust & dirt collecting on the lubricant, and a non working choke. This especially true for any car operated on roads treated with salt & sand in the snow-belt. That aggressive fine air born grit is nasty stuff for carburetor linkage.

Just give all exterior parts a good cleaning, and if needed, dress any worn pivots & rod ends with a small fine file to relive any worn spots. This should return binding free action of any linkage.

Bill
Author:  ESP47 [ Fri Dec 17, 2010 8:59 am ]
Post subject: 
Author:  scottdart [ Sat Dec 18, 2010 3:56 am ]
Post subject: 
Quote:
You can make the adjustment by holding the choke all the way open with your hand and then opening and closing the throttle to see where the fast idle cam falls. The motor can be off and cold.
I'm going try and do this today. But to be clear, what exactly am I trying to do? I know you told me what I need to do in order to allow the car to drop into a lower idle. That I need to bend the smaller rod that I pictured above, to adjust it. But what should I be looking to see happen as I expand/lengthen the rod, as I think was suggested I do..?
When I was bending the linkage to the pull-off I could see the results of what I was doing, E.I. - the choke plate/flap was closing more and more as I adjusted. Now I just need to know what I'm wanting to achieve and what should I be looking to actually, literally see happen as I make this next adjustment.

Thanks and I'm excited to hopefully get this done.
Author:  Aggressive Ted [ Sat Dec 18, 2010 11:00 am ]
Post subject: 
Scott,

Your trying to lengthen the rod just enough so the bell crank/cam will allow the carb to come off high high idle cam and go to the normal idle stop.

Normal idle speed should be 600 rpm. Some later cars were 750 with all the pollution control equipment.

Let us know how it goes.
Author:  scottdart [ Sat Dec 18, 2010 1:49 pm ]
Post subject: 
Ok so I very very slightly bent the linkage and started up the car. Cranked right up and the fast idle screw was resting up on the highest point of the fast idle cam (as it should initially). After a few sec I tapped the gas and the idle kicked down a bit and the screw was now resting at the lower part of the cam -but still on it. Then after a bit I tapped the gas one more time, and the idle screw was now OFF of the cam completely. So I think this is what I was looking to do, to have the screw be off fast idle cam.

Question: When I tapped the gas the first time after cranking, I could easily here the engines RPM drop down as it dropped lower on the cam. However when I tapped the gas the 2nd time, the RPM's did not drop even though the screw was totally off the cam. I even thought that maybe the car won't go into a lower idle unless it's at normal operating temps. So I tried that, but w/ no luck. I don't have the proper tools to know what my RPMs are, but I know my car should drop at least 1 more time to a lower idle. It did actually do this for awhile ..up until it started getting consistently cold that is.

So what should I look at now? Should it drop to a lower idle after it comes off the cam? What-cha think? What next?
Author:  Reed [ Sat Dec 18, 2010 2:08 pm ]
Post subject: 
The biggest idle drop will be from the highest step of the cam to any other step. It should drop from 13-1400 down to about 1100, and then gradually work its way down to about 750-800 RPM. The final drop from the bottom of the fast idle cam to the curb idle screw will ony be 50-100 RPM if everything is adjusted properly.

Sounds like you need to get a hand held tachometer and verify your fast idle and curb idle settings. Fast idle should be in the 1300 RPM range and curb idle should be in the 750 RPM range in neutral. Get a factory service manual (or check your underhood sticker) to know for sure.

Adjusting the idle is literally as simple as turning the screw. The Holley 1945 service manual ad video I linked to earlier should give you the procedure. Hand held tachometers are cheap. You can probably find one at a thrift shop, pawn shop, or on Craigslist for around $5.

You are almost there! Keep going.
Page 2 of 3 All times are UTC-08:00
Powered by phpBB® Forum Software © phpBB Limited
https://www.phpbb.com/