The Stovebolt Site Forums The Shop Area Engine Shop Carter YF 2100s - incorrect throttle body

I recently won an EBay auction for a YF 2100s. That model fits a 235 and has a 2- 15/16 base.

Upon unwrapping, I thought the base looked small. The tape measure confirmed it. Apparently, someone swapped the 2 - 11/16 base onto the carb. I never explicitly asked about base size, because the model # was correct for my application.

Set aside for a moment the issue between me and seller. (He seems reasonable and willing to work with me and I also know that it wasn’t sold to me as a working carb).

IF (capital IF), I decide to make a run at using the top 2/3 of the carb and finding the correct throttle body, I need to know what I’m looking for. A comparison to a 2101s I own, shows a casting number of 788 on the large body and a 630 on the smaller one. I’m not inclined to rob the 2101s base for a couple reasons: 1). Hate to mangle complete carb. 2). The throttle linkage looks altogether different.

The 2100s is a manual choke and the 2101s is auto. Appears to me that the auto choke base has a different linkage to which the choke/throttle connecting rod on the manual carb would not attach.

Will try to attach some pics later. Appreciate any insight in the meantime.

If you decide to swap bases, be very sure all the passages line up properly. I seem to remember hearing that some of them were drilled AFTER the pieces were assembled originally, to assure proper alignment.
Jerry

That is a bummer, seems like it is always a gamble with an old carb. I understand that you don't see the right ones too often and when you see something on ebay pop up, my instinct is to buy it because of the long hunt versus need on the project. It happens to all of us trying to find parts for these trucks. Wonder if carb king would have the base you need.

Yeah, this hobby brings out the worst in me sometimes. Always an internal war between my internal detail freak and pragmatist. Any given day, you never know which "me" might win.

Have a Rochester B that seems to run OK, but I think it could run a lot better. That led to the purchase of the 2101s, which I got a great deal on. It sat awaiting a rebuild long enough that I had time to reconsider. Dang, I really like the hand choke/throttle and won't have it with that carb. Which sent me a-lookin' for a manual choke YF. Got another (so I thought) good buy on this one and then discovered the throttle body issue.

I SHOULD just wave the white flag and rebuild the 2101s and learn to live with the auto choke. Or better yet, don't fix what ain't broke and put up with the B for now.

But I'm already half way down a new rabbit hole. A familiar feeling.

We used to use M-80's to get the rabbit out of the hole

Maybe you have just posted the problem with the 2101s.

The 2101s should have the number 1121.
The 2100s should have the number 1127.

The 788 base is from a much earlier carburetor.

LOTS of folks out there that seem to think they can switch throttle bodies indiscriminately, as indicated by you receiving one with even the wrong size base, and having another with the wrong throttle body. Generally, the results of the switch are much less than desirable. The Carter engineers did NOT make all the different parts simply to shaft the stockholders out of a higher dividend. Engineers really do things for a reason.

Maybe now you know why you are getting "great deals".

Jon.

Appreciate the info. I will take a closer look tonight. The numbers you reference, are those raised (cast) or stamped?

Stamped, the cast (raised) numbers are meaningless (well, at least for identification).

EDIT: more time to further explain. The raised numbers (and often letters) found on carburetor castings are referred to by enthusiasts as "casting numbers". The numbers were used internally by the carburetor companies as a number for a "casting blank". A casting would be made with certain physical characteristics (called a casting blank BEFORE machining), but then this casting could be machined a number of different ways to use for different applications. Sometimes these differences are quite obvious (will give some examples) but often the differences might be the width of the idle transfer slot, or the diameter of the idle air bleed.

For obvious examples, consider the throttle bodies used by Oldsmobile and Pontiac 2-barrel carburetors in 1957:

(1) Olds J-2 front carb - not machined for idle screws, 1/8 inch pipe tap on rear of casting
(2) Olds J-2 rear carb - not machined for idle screws, 1/4 inch pipe tap on rear of casting
(3) Olds J-2 center carb - machined for idle screws, 1/8 inch pipe tap on rear of casting
(4) Carb from Olds with single 2-barrel, machined for idle screws, 1/4 inch tap on rear of casting
(5) Pontiac tri-power rear carb - not machined for idle screws, and no vacuum tap on rear of casting

Using casting numbers only to interchange parts is often an exercise in futility! Unfortunately, many try this, and then sell the result cheaply on ebay because they couldn't make it work!

Jon.