Carburetor

cohammer60

cohammer60

Senior Member
What would you suggest the best carburetor for my 1974 bronco that has a 289 in it . It was said to have a 302 in it when I bought it but manifold says 289. Motor runs great on minute then won't crank then runs rough . Can't get old carb adjusted just want to change it. Has an autolite 2100 with electric choke on it . Carb has been rebuilt.
 

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Could be an electrical problem, not the carb.

Have you gone through the points and plugs (tune up)?
 
It wouldn't be a surprise to have a 289 manifold on an early 302, that one is from '66.
If you want to confirm what engine block is in the truck follow the links in this thread. http://www.fordbarn.com/forum/showthread.php?t=164840

Occasionally not cranking sounds like an electrical problem. Among other things double check both ends of the starter cable. The last two cars I worked on with 'bad starters' had a loose cable at the starter. The nut had become slightly loose in the past and arcing melted the bolt threads. The nut was tight on the burned starter bolt threads (only) but the cable lug was still loose and arcing because it wasn't really tight. (put on an extra washer)

Runs rough sometimes? Check all the vacuum fittings & advance diaphragm on the dist. for leaks.
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First thing to try is to remove idle adjustment screws and blast air thru the holes. Reinstall idle screws. Screw screws in by hand till seated and back out 1 and 1/2 turns. Let me know what that does.
 
Have a ready to run distributor kit on it and it fires up for a moment then keeps going dead . Thought I fixed problem by replacing carb gaskets and it fired up and ran great , pulled it out of garage and parked it , went back 5 hr later and it start go dead would not run without very high idle . Put in gear hoed dead . I ran jets in and backed out 2 turns .
 

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I think you may have more than one problem. If it were mine, I would first replace the condenser in the distributor. They can be good one minute and bad the next, new out of the box or 20 years old. If there is a plate under the carb, it sounds like it has corroded and you have a vacuum leak.
 
The carb tag number shown is for a 390 cu in engine. The carburetor would
have a large 1.23 venturi. It is NOT a good choice for a 289/302 in anything, car or truck. Large main jets, in the order of 55 or 56 are also likely in place, again not consistent with a 289/302.
Your best option is to get a 2100 sized with a 1.08 venturi, 1966-1974, IMHO.
Next best would be a 2100 with 1.14 venturi, attention given to the jets used.
 
the 2100 isn't my favorite carb, I build a mess of them and a consistant problem I see when I take them apart is that the owner will try to rebuild it himself and 'puts a kit' in it. Except there is this obscure funny looking spring that attaches to the shaft the float pivots on. The spring has some goofy bends in it and most people think it is to keep tension on the float and they roll the spring under it. What that spring really does in locks the float down, it goes over and attaches to the backside of the needle & seat, theres a groove in the N&S for it. Unless it is clipped behind the needle & seat the float will rise up when fuel flows into it and won't let the needle & seat act proper.
It'll act like you describe if the spring isn't clipped, did the PO say the carb had been rebuilt recently? That is probably why.
If you want to replace it I'd go with a 350holley, esp one from an International as they have an improved idle circuit over the holley, the manual choke on them is better than the holley as well due to 'high idle' devices.
 
oj said:
the 2100 isn't my favorite carb, I build a mess of them and a consistant problem I see when I take them apart is that the owner will try to rebuild it himself and 'puts a kit' in it. Except there is this obscure funny looking spring that attaches to the shaft the float pivots on. The spring has some goofy bends in it and most people think it is to keep tension on the float and they roll the spring under it. What that spring really does in locks the float down, it goes over and attaches to the backside of the needle & seat, theres a groove in the N&S for it. Unless it is clipped behind the needle & seat the float will rise up when fuel flows into it and won't let the needle & seat act proper.
It'll act like you describe if the spring isn't clipped, did the PO say the carb had been rebuilt recently? That is probably why.
If you want to replace it I'd go with a 350holley, esp one from an International as they have an improved idle circuit over the holley, the manual choke on them is better than the holley as well due to 'high idle' devices.
Click to expand...

I take a big exception here. The spring spoken of IS a Float Dampner Spring, and it is installed with it's short end under the hardware end of the float. A Float Rod Clip holds the float keeping it and the needle lifting from fuel pressure and chamber filling, and it clips to the groove in the outside of the seat.

The spring is optional. I dont know of any rebuild kits that include it, and most kit diagrams dont even show it. It can be purchased individually from some mail order suppliers.

I've rebuilt about 200 of the 2100 series. Properly done and matched, they are hard to beat. But they are not universal Holleys. Even though they are simple, I dont have time or inclination to list all the crap that can go wrong or be found wrong, making do-it-yourself for the novice more difficult than it would seem.
 
Also check the condition of the "ready to run" copper braided wire that grounds to the dist housing and the dist plate. seen a lot of them broken.
 
46yblock said:
I take a big exception here. The spring spoken of IS a Float Dampner Spring, and it is installed with it's short end under the hardware end of the float. A Float Rod Clip holds the float keeping it and the needle lifting from fuel pressure and chamber filling, and it clips to the groove in the outside of the seat.

The spring is optional. I dont know of any rebuild kits that include it, and most kit diagrams dont even show it. It can be purchased individually from some mail order suppliers.

I've rebuilt about 200 of the 2100 series. Properly done and matched, they are hard to beat. But they are not universal Holleys. Even though they are simple, I dont have time or inclination to list all the crap that can go wrong or be found wrong, making do-it-yourself for the novice more difficult than it would seem.
Click to expand...

Thats the 'spring' I was speaking of, when you call it by the proper name people don't understand it, it looks like a spring.
 
Found this carbeurtor in my pile of parts not sure if it would work . Came off 1964 truck it is a 2100 with a manual choke.
 

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That is probably from a 292 powered truck with 1.02 venturi carb. Look inside the cast-in circle, behind the accelerator pump rod, on the side of the float bowl.
The number is the venturi size.

Yes it would work. It will result in a little less max. rpm, in the neighborhood of 3800-4000. Some early 289 cars came with the 1.02 2100. They then changed to 1.08 and 1.14 sizes.
The manual choke would be good for your app. But make sure the choke isnt missing parts, as they often are, and finding replacement parts for the man. choke is difficult.
 
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