The Stovebolt Site Forums The Shop Area Engine Shop Carter carb linkage problem

Okay guys, per this forum recommendations I finally tracked down the infamous Carter YF2100S carb everyone says works so well for my 59 Chev 3100 235 six. Had it rebuilt and attached it to the mani. (see Pic).
Here's the rub, the vertical linkage the comes up and attaches to the carb bracket wont attach. When I compare the Roch "B" linkage it rests(idle) at say, 4 o'clock. The vertical linkage pushes up which opens the throttle wide open to about 2 o'clock, spring pressure pulls it back down to about 4 o'clock(idle). My Carter rests(idle) at about 6 o'clock (directly over the intake manifold, the opens to max about 4 o'clock?? The carter bottom piece (base perhaps) has numbers cast (1-788). Per google pics, most have this same base, however, the throttle bracket looks to be at a different angle allowing the rod to attach at 4 o'clock. Hope this isn't too confusing!!!
NOTE: In the pic, that is the carb at full throttle, TW. At rest, it sits at 6 o'clock over the top of mani. Linkage can't work

Try looking at the block were the linkage attaches to it there may be a hole close by that will make it right

I understand your question, but this is specific to the throttle bracket on the base. The angle/throw is incorrect. Unless this can be adjusted, it will not work properly.

Hard to understand your explanation except to say you are having trouble with the linkage from pedal to butterfly. If you are a machinist. you are smart, handy, a designer, problem solver, innovator. It seems you are talking about rods. Make or modify rods to do what you want. Don't fret over it. Fix it.
Not sure where the o"clock positions are referring to. I know it is hard to explain a issue like this to us who are not there to see it. We want to help but no one will be able to give you a specific set of instructions. As a mechanical design engineer (ret), I recommend mocking up with stiff but bendable wire and possibly string to come across a solution, then use rod stock or the rod material you show. Probably want to leave off any return springs during mockup at first.
There may be someone here who can send a set of pics of what they did with the same motor/carb/TF truck.

The technical term for this is "Fiddle, Diddle and Think, repeat"

Yes hard to describe. I figured because this carb was specifically designed for this engine, there should need to be any modifications. It is a extremely popular card also. Certainly, others have dealt with this issue. Maybe I'm missing something here. The butterfly linkage is out of timing, linkage cannot attach. I'll keep researching. Thanks for the reply.

kind of off subject and not aimed at you at all. I find it funny when the internet advises to get an exact carb for year and motor. i've used all kinds of Rochester/some carter/ carbs on all kinds of mostly chevy motors. They all squirted gas/vapor into the manifold and motor ran good. Maybe it was 60 years of luck. i never worry about gas mileage, it's a waste of time for just a town driver. You can spend hours and lots of money to save 10 bucks a year.

What direction are you calling 12:00 o' clock?

Hopefully straight up somewhere. If not, we are all in trouble.

Sorry, 12:00 would be straight up(at noon time). Viewing the carb from the firewall towards the radiator( so that the bracket would be facing you). On the Rochester idle would be at 4:00 to full throttle 2:00. The carter, idle is at 6:00 to full throttle 4:00.

Can you point to the thing you call "a bracket"

YF2100S pics attached. First Pic has the bottom butterfly closed: approximately 4:00. Second Pic butterfly is fully open: approximately 2:00.

It looks like the throttle body on the OP's YF2100 carb is for some other application. If the closed throttle position has the crank arm at 6 o.clock, a vertical linkage pushrod isn't going to work. Maybe it was from a car where the carb mounts with the throttle shaft crossways and the accelerator linkage pulls the crank on the throttle back. It doesn't look much like Mike's picture.
I'll bet Jon (carbking) could weigh in and solve the mystery.
Here's a pic of my YF 964S (an earlier version of the YF2100S) where the linkage attaches is at about 3 o'clock and pushes upward.

Really difficult to judge depth of field from a picture, but the bracket appears to have been bent went it was shipped to you. Looks like it is bent inward.

Jon

Is it possible your 2100S has the wrong base installed? I have 1-788 casting base plates that have different staked on throttle linkage arms. (the 2101S has 1-788 base with a different linkage design) The 2100S base casting for the 235 Chevy engines has the hole the for the linkage sitting at about 4:30 ay idle and 1:30 at wide open. My linkage looks different from your picture. The correct 1-788 base should attach with no alteration to the rod from the engine. Perhaps Carb King will ring in with the answer.

Stock picture

The base of my 2100 also has the 1-788 base. Perhaps the OP carb had a different throttle shaft installed sometime in the past?

Is there a stamped number on the underside of the flange assembly.

The 1-788 is an internal casting number, and should not be used for identification purposes.

Jon

The carb that I posted pics of does have a number stamped on the bottom of the base. It reads 1127. Pic attached.

Thanks guys should have done this sooner. Pics represent the Roch-B on left/YC21100S on the right. closed throttle(idle) and fully open. The bracket I'm referring to is the one the vertical throttle linkage attaches through the hole. It moves up/down vertically. The bracket has no numbers, only a patent stamp. Underneath the Base is stamped 1127. The bracket is not bend or damaged in any way. Is it possible to clock this counterclockwise to match the Roch-B or is this base belong on something else. The carb is stamped on the backside from pic with YC2100S. Thanks for the help hopefully this may answer some of your questions.

Interesting how we have identical carbs yet the throttle bracket has a different orientation.

Yeah, it's odd. Also, the "YC" designation is something I haven't heard of before.

Fwiw, attached Pic shows the drawing of the throttle shaft and lever assembly for the YF2100. I don't know how that would relate to a YC2100.

Sorry Mike, you are correct it is YF, not YC.

Thats what apparently, I need. Would definitely correct the throw that is required. Great help, now I need to find one!

That part (3-889S). what is that part called?

It's the throttle shaft and lever assembly. The full base assembly is part number 1-1129S. It is shown in the drawing and is only partially in the pic I sent. That part includes all of the parts in the base. I'd search for both and go with whichever one you find first.

Thanks again to everyone for the help. My luck to get stuck with the odd part.

I don’t have my 2100 in front of me. But I do think your throttle lever looks different than mine. Like maybe it had a different throttle body swapped under it as some point?

I’m not sure if you have a “throw” problem or just a “rod length” problem. But either is correctable. Measure your how far you can get the vertical throttle rod from the engine to move up and down. Then measure how far the lever on the carb will travel from its lower most position to its upper most.

I think it’s more likely that you have a rod length problem. When I get motivated enough to go brave the extreme cold, I can go out and take a pic of some mods I did to mine. All-thread and one or two throttle pivot linkages, or heim joints, will make it operate a lot smoother than the original.

On another note….

I got a little lost in the discussion about numbers. Was there any conclusion as to whether you have a throttle body or shaft from a different model YF? I’m confident you can get full throttle and closed throttle positions straightened out. But if that is the wrong throttle body, there’s a ~slight~ chance you don’t have the right vac passages in the right places to make it run properly.

Adding a bit more information to the thread:

Throttle body 1-1129s is unique to the 2100s carburetor
Throttle shaft and arm 3-889s is unique to the 2100s carburetor

When the OP called, I suggested he look at the orientation of the throttle plate in the throttle body to make certain it was correct. Given the offset of the throttle body, if the throttle plate were installed on the wrong side throttle shaft's normal orientation, it could change the clock position of the throttle arm. Don't know that this is the answer, but certainly worth a look.

Jon

OK, too doggone cold to work, so I dug through more boxes. I WAS out of 2100 carbs that I knew where were. One of these days will find ALL my carbs (yeah, right!).

The cleaner of the two is an early production 2100s (no exact date code).

The grungier of the two is a late production 2100s produced in April of 1956.

In the other two pictures, it is apparent that the hole in the throttle arm when closed is approximately 4 o'clock (using "up" as a 12 o'clock reference), and is located at approximately 2 o'clock when the throttle is open. This agrees with the OP's comments about the Rochester.

And no, without scanning an aperature card, I don't know all differences that exist between the early and later production, other than the obvious change to the stamping of the part number. The tech sheet does specify that the position of the vacuum port was moved by 0.005 inch, and the pump discharge valve was changed from the ball and weight, to a pointed weight without the ball.

Jon

It makes sense that the throttle lever position on a Carter 2100 should be in the exact same position as a Rochester, as they're supposed to be a drop-in.

Also if the throttle plate was installed incorrectly, either upside down or on the wrong side of the shaft it would affect the position of the throttle arm.

A simple fix is to add a short piece of flat stock like I have circled in the bad picture of my twin W-1 Carters. I needed the throttle to open from the left side of the intake, where the stock linkage pushed up, mine pulls down. Mine is bolted on with a 1/4-20 nut and bolt and allows for adjustment. Mine has the 1/2" x 1/8" flat stock going across center and pulling down thus lifting up on the arm. Yours would be just lifting from a different point. You can always change out the throttle shaft later if you find one, with this modification you can get the truck up a running to see if it's worth the effort.

I found a little better picture.

Joe

Thanks guys. Quick question:
When you look down through your carb(2100S) and you see the round/oval throttle plate, is it ontop of the rod or below it? Mine is ontop, not below. Trying to figure out if the rod is 180degrees out which would change the orientation. Also, in examination , this bracket I keep referring to that is attached to the throttle rod, is peened onto the brass rod. Doesn't look tampered or altered with?

Thanks JW, my lower body has the correct casting# and stamp underneath, so it is definitely correct for the 2100S. The linkage is stock and should not need modifications as it is a direct replacement for the Roch-B. We're thinking perhaps the throttle rod was installed upside down? or something. None of this makes sense. It cannot work the way it is for sure. In the idle position it has to be around the 4 o'clock orientation.

Thanks Joe had both carbs on the shop bench today studying that very though. Attaching the flat bar needs to be where the center of pivot which means i would need to weld the flat bar with a tig weld. I believe I can do this without excess heat allowing the throw of rotation to be correct with original. Trying to locate the correct throttle rod and bracket may be tough. These carbs are already difficult to source. But you are right it would satisfy to get me going.

If you look at the picture from Gray Ghost above, that is looking at the throttle shaft and plate from the underside up. The throttle plate is mounted on top of the shaft, if you look from the top down.

From what I can see zooming in on your throttle plate arm, it is definitely different from the other pictured YF2100S carbs posted. Very good probability that the throttle body is not correct for the YF2100S main body (or someone installed the wrong throttle arm/rod when rebuilding). Not surprising considering how some rebuilders just grab what they think are the right parts and assemble/sell without being sure all are correct.

You may need to search for/purchase another rebuildable or parts carb to scavenge the correct throttle body to put everything where it belongs and functions correctly.

Never mind on the throttle plate question. In review of part 3-889s that grayghost posted, it shows the throttle rod flat cutout on the top which means the plate would be above as mine is. Which means the rod is correctly installed. Which inturn means the bracket can't be oriented differently.

Jon, FYI- Mine has the exact 2100 stamp as the late production(dirty one).

Yes Dan you are correct. I'm convinced the body is correct. Someone likely out this rod in so that you could use a wire type accelerator linkage that normally attaches to the valve over and push/pulls the throttle bracket in and out. This would work well for that application, not so much for us with OEM rod linkage.

I think you're right Joe.