The Stovebolt Site Forums The Shop Area Engine Shop Carter W-1 Carburetor

I have a 51 GMC pick-up. My carburetor is stamped with "CARTER W-1" but it has no tag attached to it. I'm trying to get a rebuild kit for it but want to make sure I get the right one.
Any help would be appreciated.

Contact carbking on this site.

I can almost guarantee you that you won't find a kit locally. I went to every auto parts store in town and NONE of them had it. They did have the Carter Y-F, but that one won't work.

Look at the top of the carb where the air filter goes. Here\'s a picture of mine

Is there a little diagonal tube coming out of the side (where the plunger and the needle valve and the float are)?

That's a 41-48 carb. If the tube isn't there, then it's a 32-40 carb. I'm fairly certain that they take the same rebuild kit, but I'm not 100% sure.

You can get the rebuild kits at American Classic and Jim Carter

ETA: It looks like my synchronization scripts between the 2 web servers haven't come through yet. If the picture doesn't show up for you, try again in a little bit.

I found the following Carburetor rebuild kit at Discount Auto, just don't know if it is the right one?


:confused: Parts America.com

Doesn't look like it.

It has no detail, so I have no clue what this is even for. As I said before, I went to EVERY auto parts store in town (NAPA, Carquest, Autozone, Advance, and Thirlby's) and NOBODY had the kit. If my Advance doesn't have it -- and doesn't even know that it exists -- then I'm pretty sure that yours isn't gonna have it either.

The W-1, while a solid carb, is REALLY OLD. Most car parts places don't have parts for anything older than 1960. I'm lucky, because my favorite FLAPS has data and parts for stuff back to 1946 on some things, but I'm unlucky in that they don't have any data for other items -- like the carburetor.

Check out the two vendors that I mentioned in my previous post. They have the right kit. I've linked right to the pages in their stores where the rebuild kits live, and you can buy them quickly and easily without any muss or fuss.

The W-1 on my 38 coupe has the same carb as in Brendan's picture. It's stock from the factory. There may be a difference between the car and truck carburetor. The only thing a kit will give you that you don't alread have is gaskets and an accelerator pump plunger. The brass washers for the brass plugs won't seal and keep the gas from leaking out. Carbking advised me to put a drop of blue loctite on the plug threads to seal them. If you don't have broken or missing parts (like the plunger) you don't need a kit. The kits cost around $50 each. Clean the carb in carb cleaner, re-assemble using loctite on the plugs, make a new bowl gasket using rubberized gasket material and you should be good to go. You can get kits at Chevs of the 40s, Obsolete Chevrolet Parts and The Filling Station. Obsolete Chevy Parts and The Filling station have W-1 kits for both the flat shaft accelerator pump and the round.

Quick identification of Chevrolet W-1 carbs (remember that Carter made 128 different W-1's, so they were used on other than Chevrolet)

1932 - high idle screw, no vacuum for distributor
1933 - high idle screw, distributor vacuum port
1934,35 - 2 screws air horn, 2 screws bowl cover
1936 - 3 screws air horn, 2 screws bowl cover
1937,38 (different, but to tell these 2 from other years):
4 screws bowl cover, round pump, turned under throttle arm
1939,40 - same as 37,38 but conventional throttle arm
1941-1948 - flat accelerator pump, no fast idle (flat rod)
1949 - different flat accelerator pump, fast idle rod.

These are for the Master and Truck carbs; the Standard carbs are different yet.

There are EIGHT different kits for the above listings. There are several more for the Standard series carbs.

Oh, almost forgot, the 1932 truck has a smaller venturi, and has the letter "T" cast on the side. That makes 9 different kits.

Jon.

Oy vey.

Thanks for all the help!!!!

The 1937 and up W-1 is one of the better 1 barrel downdraft carburetors ever built (MOO). When Carter brought out the W-1 (and its big brother, the W-2) in 1932, they had some "teething" problems. However Carter (unlike some other carburetor companies) recognized the problems, and by 1937 had corrected ALL of the major problems. Changes after 1937 were less dramatic than those previously.

To "thumbnail" some of the major changes:

1934 - major redesign of idle circuit. The initial idle circuit of the 1932 design was a hold-over from the updraft series carburetors, and basically, the idle mixture screw was an inverse measurement. The move of the mixture screw from the top of the casting to the lower section of the casting allowed use of the type idle circuit used by Carter until the end of the O.E. Carter carburetor.

1936 - change to 3 screws holding the airhorn eliminated breakage due to instability.

1937 - change to 4 screws holding the bowl cover eliminated warpage of the bowl cover (another company SHOULD have taken note of this!).

1941 - change to flat accelerator pump. This change was not an "improvement" per se, but was a change which allowed for a slight reduction in the cost of production (and later rebuilding - then); as the cost of the complete "machine assembled" accelerator pump was less (then) than the labor to assemble the older style pump.

1949 - major change to accelerator pump linkage (why, I haven't a clue); plus the addition of the link from the choke to the throttle, which acts as a manual "fast idle". Many like to use the 1949 carburetor as the center carb on a 3x1 aftermarket setup because of the fast idle feature; and use the 1941-1948 carbs as the end carbs. The disadvantage of the 1949 carb is that the accelerator pump for the 1949 carb is unique in design; and as far as I am aware, unavailable except from us. We hand-make the pump in the shop upon order. This makes the 1949 the most expensive of all of the W-1 units to rebuild.

The major problem today with the W-1 is simply ignorance (certainly fixable). Often, people assume that, since most parts physically will interchange among the different models, that the interchange will work. The calibrations were "tweaked" with almost every year. A 1935 metering rod may not work with a 1936 main jet; even though, unless one checks each item against the specs, they "look" the same. There are also some wear issues with the earlier units, but these issues will be corrected by any competant mechanic.

With the exception of the 1932 and 1933; ALL, if properly rebuilt will perform extremely well. The 1932 and 1933 normally have some idle issues, but will run very well above idle.

As with any other carburetor, if one uses ethanol, it may be necessary to "fatten" the calibration slightly (for E-10). Fortunately with the W-1, this can be done by replacing parts.

Jon.

Stunning info Jon, thanks for sharing .

That's great stuff, Jon.

You truly are the Carb King.

A few years ago, the editor of one of the national car magazines asked me to do an article on the W-1. It took awhile to disassemble, and restore one of each of the different W-1's for comparison pictures; as well as accumulate all the calibration data. By the time I had finished, editor had moved on, and new editor was more interested in 350's than in W-1's (his loss). Still looking for a large magazine to publish the article. Thought I would share some of the points in this forum. Glad you liked them.

Guess I should not have been so slow.

Jon.

What do you mean by the following?

"As with any other carburetor, if one uses ethanol, it may be necessary to "fatten" the calibration slightly (for E-10). Fortunately with the W-1, this can be done by replacing parts."

I have run 10% ethanol in a 37 Chev with W-1 with no apparent problems. I am rebuilding a different W-1 now, so if a change is needed, now is the time to do it.

Please copy answer to cisgww@aol.com.

Thanks! Greg


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I think the key is it "may" be necessary. If you're not experiencing a lean condiditon you probably don't need to do anything. I have no problems with my 38 W-1 on E10 either.

If the needle in the needle and seat assembly is worn to the point where you would be fouling plugs on gasoline; it may be just right for E-10. LOL

The following are our recommendations for street use of modern fuels with and without ethanol:

Modern fuel/no ethanol - lower float levels 1/32 from specification
Modern fuel/ethanol E-10 -lower float levels 1/32 from specification,
increase main metering circuits fuel flow by 5 percent.
Modern fuel/ethanol E-15 - lower float levels 1/32 from
specification, increase idle jet flow by 5 percent, increase main
metering circuit flow by 10 percent.
Modern fuel/ethanol E-85 - nope, not going there at all, good luck to
any that try it!

If the customer resides at a higher altitude than 4000 feet, then a
different calibration is used.

If the customer tours with the vehicle, and passes through different
major altitude variance; we suggest the use of the Carter AFB, and
cut custom metering rods for different altitudes.
Typically "standard" calibration is used for sea level to 4000 feet;
1 size lean from 4000 to 6000 feet, 2 sizes lean from 6000 to 7000
feet, and three sizes lean from 7000 to 8000 feet.

Jon.

Just re-read my comments. These were originally done for 8 cylinder vehicles with four barrel carbs; hence the reference to the Carter AFB.

Not recommending to put an AFB on the stovebolt 6 (although a Carter 9400 - 400 CFM) will work very well on a worked over 6.

Jon.

Hey Everyone! I tried posting a question last week and it must not have gone to the correct page. I'm looking for the throttle / choke bracket that goes on the 49 Carter carb. Can anyone point me in the right direction?