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-   1973 - 1979 F-100 & Larger F-Series Trucks (https://www.ford-trucks.com/forums/forum38/)
-   -   best fix? choke/carb/mainfold question (https://www.ford-trucks.com/forums/1151375-best-fix-choke-carb-mainfold-question.html)

meborder 03-29-2012 12:25 PM

best fix? choke/carb/mainfold question
 
Looking for a quick pole of opinions.

I've got to do something with my '79 with a 460.

the choke on the carb has been completely hacked and is almost completely non-functional. A PO turned it into a semi-functional manual choke. It starts hard and sometimes requires a little bit of work to keep it running once started. It will also stumble/stall if you get on the gas too hard when cold. (i presume this is a problem with the secondaries kicking in when cold) ... it needs some work.

so i'm exploring some options. the way i see it, for me right now, i have 3 viable options.

#1- pull the carb, rebuild it, and try to fix the choke. The problem is, i have no idea what they hacked when they attempted to "fix" it, so it could take a while to fix assuming it even can be. I would rebuild the carb while i had it out.

#2- replace the carb with a summit or edelbrock with an electric choke and just block off or remove the non-functional emissions equipment (EGR, ect)

#3- Go the extra step and replace the intake with a decent aftermarket unit along with a new carb.

I'm thinking option #1 is the least expensive, but most time consuming. Option #3 may be the best, but most expensive, and may nearly as long as option #1.

Option #2 scares me in that the old manifold may not let the new carb do its job as well as a new manifold would. That is to say, I'm afraid of running into metering problems that could have been avoided if i would put on a new manifold. Also, I'm not sure how the non-functional EGR may affect the way the new carb will work.

so ... i guess i'm looking for some input.

The truck is my heavy hauler, and haulin' season is right around the corner, so i'd like to make the truck work as well as i can, but with a baby on the way, funds are not exactly un-limited. I want to spend money wisely, and get the best bang-for-the-buck that i can without wasting mone on something that i could have done without, that's all.

thanks in advance!

ChiefM 03-29-2012 12:39 PM

#3- If you have the money,

Ohiocrewcab 03-29-2012 01:30 PM

All 3 are good ideas. What carb is on there now? Any engine mods? Jegs sells factory replacement carbs for about 250. I would just replace the carb for now.

cowboywanabe 03-29-2012 04:20 PM

If you go with #1, you can attach a manual choke cable and be able to open/close the choke using a knob inside the cab. You should be able to find a universal manual choke kit at the parts store for a few bucks. The kit would have all the parts you need.

When starting, it takes a little more involvement on your part to set the choke, then adjust as the engine warms up. If your carb is tuned properly, it should work just as good as an auto choke. I've got a manual choke on my Edelbrock and it works great.

meborder 03-29-2012 06:04 PM

That's what the PO attempted to do ... not for sure why, but it does not work very well. There is not sufficient adjustment with the manual cable, my choices are to have a choke that either does not close all the way, or one that does not open all the way.

It also won't catch the high idle right. It will catch the first notch, but that wont keep it running when it is colder (weather like today)

I hadn't seriously considered a reman from the parts store or Jeg's ect due to some bad reviews i've read on this forum.... perhaps they are a viable option i should be considering more seriously.

it is a holley type square bore carb. Not sure what model number .... once it's warm, it runs pretty good with acceptable milage and power.

I wish i knew how to fix the choke, i really think that's the only thing wrong.

the engine, as far as i know, is bone stock.

OldStyle 03-29-2012 06:11 PM

If the choke is the only problem then why don't you just put a new electric choke cap on it? Then you just have to play with the adjustments; shouldn't be too hard. There are spec's for adjusting the linkage arm and the speed. Can you find a model number? Maybe post a pic or two?

Here's one style: http://www.ebay.com/itm/ws/eBayISAPI...m=160773809777

and another: http://www.ebay.com/itm/ws/eBayISAPI...m=160759125339
.

meborder 03-29-2012 08:55 PM

Ok ... so here's the pics. Sorry for the poor quality, but the shed is dark and this is the best i can do without getting out the big flood light.

hopefully one of you guru's can make heads or tails of what i have or need to get squared away.

from the side:
https://www.ford-trucks.com/forums/p...ictureid=96800

From the other side:
https://www.ford-trucks.com/forums/p...ictureid=96801

from the front:
https://www.ford-trucks.com/forums/p...ictureid=96802

on the choke horn:
https://www.ford-trucks.com/forums/p...ictureid=96803

on the front float bowl:
https://www.ford-trucks.com/forums/p...ictureid=96804

hacked up choke:
https://www.ford-trucks.com/forums/p...ictureid=96805

hacked up choke from side:
https://www.ford-trucks.com/forums/p...ictureid=96806

non-functional EGR:
https://www.ford-trucks.com/forums/p...ictureid=96807

on the bright side, i'm less afraid of the EGR. I had never noticed that it is attached to an EGR plate beneath the carb. I had always assumed it was attached to the manifold as i have seen ford do on other engines....

I have no inclination to fix the emissions equipment. I realize that the carb is tuned for the EGR and such, but if i can get it to run fine and start well, i'll be plenty happy.

what do you all think? fix it or replace it?

OldStyle 03-30-2012 08:02 AM

Your truck probably came from the factory with this carb, according to the number/model. It would be jetted correctly for your engine. If the truck runs good other than the choke issue I would fix the choke; being the least expensive option.

The po installed some form of manual choke.https://www.ford-trucks.com/forums/p...ictureid=96806 You should be able to remove it with the three screws. Then replace it with a 12v choke cap, adj for proper operation and be good to go.

They also put the hot air coil in upside down.https://www.ford-trucks.com/forums/p...ictureid=96805 Lower left tube affair. Unbolt and invert.

I would also check the egr canister to make sure you don't have a vacuum leak.https://www.ford-trucks.com/forums/p...ictureid=96807 Light gray hose.

I typed a much more detailed response but closed the window and lost it....:-arrgh :-X19

Hopefully others will add their input. :-X22

meborder 03-30-2012 05:47 PM

Thanks for the tips!

If it is as simple as replacing the cap with one of the 12v units you linked to, that's easy enough.

Regarding the hot air tube ....
invert it or turn it around? I've never seen one done right, so i'm not sure exactly which way it should face, or what it should look like.

Would i even need to mess with it with converting it over to the 12v cap? Or by doing that am i simply getting it back the way ford had it to begin with?

My only other concern is if it will catch the high idle like it is supposed to once i replace the cap. Right now it will only catch the first notch, wich isnt enough to keep it running always.

I've just never had to fix a choke before ... everything i've ever owned just worked right....

OldStyle 03-31-2012 07:27 AM


Originally Posted by meborder (Post 11646487)

Regarding the hot air tube ....
invert it or turn it around? I've never seen one done right, so i'm not sure exactly which way it should face, or what it should look like.

Would i even need to mess with it with converting it over to the 12v cap? Or by doing that am i simply getting it back the way ford had it to begin with?

My only other concern is if it will catch the high idle like it is supposed to once i replace the cap. Right now it will only catch the first notch, wich isnt enough to keep it running always.

I've just never had to fix a choke before ... everything i've ever owned just worked right....

The hot air tube goes inside the manifold; see 5th pic. I'll link a write-up fmc400 did and you can see it in the pictures. It's for a 2brl but is similar. Great write-up! He's a major contributor to this site and his knowledge is un-surpassed!

Ford Truck Enthusiasts Forums - View Single Post - Choke questions answered.

If you don't use the hot air stuff, you will need to find the external tubes, then you can use a 12v cap like I linked to in my first post. Other wise if you return it to factory you can use this one:

Walker Products 102-1008 - Choke Thermostat | O'Reilly Auto Parts

During the adjustment process you will put the choke cam on the proper step and there is a screw you will turn to bring the fast idle up to spec. Not hard to do.

I have been looking for an "on-line" rebuild instructions or pdf file for you but haven't found one yet. My '79 manual is a hard copy and harder to upload.....
.


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