The Stovebolt Site Forums The Shop Area Engine Shop Carter W-1 574s or 684s?

Boy do I have a good one here for you all. I've been reading up on these W-1's like crazy and I think I have something either slightly unique, or totally wrong!

https://goo.gl/photos/QVMgBRckhKUU9cNd7
https://goo.gl/photos/EHjUALgQwjSXCTrC7


So my all-original Canadian '48 3/4t has a W-1 on it, with the tag #839987. No problem, every resource online says it's a 574s and it doesn't have the throttle-choke linkage that would make it a '49 684s. However, take a look at the accelerator pump. It is a long flat shaft, without the spring cup on the bottom, which looks mysteriously like the piston out of the '49! When I opened it up, the spring was BELOW the piston, not above it. The cork ring at the lid makes me think that a spring should not come in contact with it, therefore it should be below the piston.

https://goo.gl/photos/pWm4dqSeg6yUCRKo8
https://goo.gl/photos/KdNBcSuS2AqHFPBx6

I can't say that this is the original carb, but nothing else on the truck has been touched, so it is hard to imagine that it was changed.

Here are my thoughts, and I hope you will chime in with yours; This is either a different carb setup than anyone has seen, or someone has put the wrong piston in the pump.

And yes, before you ask, I have spoken with Carb-King Jon and he said look to the sleeve length in the pump shaft, which as you can see is full depth and I believe indicating a 574s body?

Has anyone seen anything like this? Anyone got some pics they want to swap? A 574s would be so much cheaper to get a kit for!

More Pics: https://goo.gl/photos/u9BGyxYvxu92nVqp6

Thanks everyone

Look at the bottom of the carburetor flange, it should have a faint stamping on it.

Did the pump work?
Did the carburetor run ok?

Why are you messing with it?

After all these years, I would bet that carb has been rebuilt at least once if not more, so getting the wrong kit in the correct carburetor would not surprise anyone who has been around old equipment. The stamp on the bottom flange will tell you what it is.

Joe

Is the 'bottom of the flange' the surface between the carb and the manifold? I haven't had it off yet, if it is.

I wouldn't be messing with it, except for the fact that when I give it gas, it bogs and usually stalls out. I have to very gradually give it gas to keep it from stalling. Someone said earlier that this is likely the acc pump. Thanks!

You got some good info from "Someone", replace the accelerator pump and it will go again.

Thanks, now just trying to confirm which pump it should be. I am concerned that if I try the 574s, it may not be the right one for this carb.

https://quadrajetparts.com/metering-rod-049068-carter-p-1249.html

There are two pumps that could fit the hole, the length is different so start with that. ( see link above ) Also, see the link below from Mikes Carburetors. Watch his video,

http://www.carburetor-parts.com/W-1_c_168.html

Thanks Joe. This would be much easier if I knew that I had the correct pump for the model. Also, measuring the hole depth probably won't tell me much, as they will likely both fit.

Basically, I'm hoping to get confirmation that someone put a 684 plunger in a 574.

There are two pumps that could fit the hole, the length is different so start with that. ( see link above ) Also, see the link below from Mikes Carburetors. What his video,

Joe,

Does this mean that Quadrajet accelerator pumps fit the W-1? That would be nice. I know that a Quadrajet throttle shaft bushing is perfect for the W-1

No, it will not fit. Q-jets are what they specialize in, they sell other parts as well.

Goach2, Have you looked at this site ,http://www.thecarburetorshop.com/CarterChevroletW1.htm

The 1949 carb has the accelerator spring above the leather, '48 and older has the spring bellow the leather.

Here is the 574 sheet, http://old-carburetors.com/Chevy/pages/001-Chevy.htm
and next page, http://old-carburetors.com/Chevy/pages/002-Chevy.htm.

Yes, I've seen every page online that has to do with these carbs. I'm going to have to assume someone put the wrong plunger in it years ago. I hope the 574s is the right one, I just hate wasting time/money!

684s:

Pump cylinder height in the bowl is approximately half-way from the floor of the bowl to the top of the bowl.

Accelerator pump skirt is at the bottom of the pump.

Pump return spring is above the pump (between the skirt and the bowl cover)

574s:

Pump cylinder top is flush with the top of the bowl.

Accelerator pump has metal cup below the leather skirt to hold the pump return spring.

Pump return spring is located below the pump (between the pump skirt and the bottom of the pump cylinder.

And (no offense meant) while "a picture may be worth a thousand words", it also takes 100 times longer!

Jon.

Thanks Jon,

Based on the tag, lack of choke-throttle linkage and full height of the cylinder, I'm going to call this one "The wrong pump in a 574s".

Thanks everyone.

Goach - the pump return spring on the 574s is also different, so when you order a kit, make sure you also get the pump return spring.

Jon.

That is a good tip, Thanks Jon.

Reviving my own thread, as 3 years later and I'm finally rebuilding my carb with the kit I purchased from the Carb King. One question I have is the manifold gasket that comes with it; if I already have the thick 'insulator' on the intake, do I also need this gasket under the carb? Thanks!

Carter supplied a thin gasket part number 1A-17.

What Chevrolet did with the thin gasket, and thicker spacer, I do not know.

Jon.

Carb's in, seems to run fine, but still leaking...
https://photos.app.goo.gl/15PPiCW8n7QURemn7

My artificial eyes are not as good as the real ones once were.

Where is the leak, and when does it leak?

Jon.

The pump-jet passage is leaking for sure, the check valve passage plug may be as well.

Copper gaskets for the plugs are provided in repair kits.

It is quite difficult to get these gaskets perfectly centered to avoid leaks.

The gentleman who was the chief instructor for Carter's Carburetor School taught me NOT to use the copper washers, rather to very carefully place a half drop of BLUE Loctite on the plug threads. Once complete, allow the carb to sit for 24 hours to allow the Loctite to dry. CAVIAT: Blue, blue, blue, blue NEVER red! Blue can later be removed, red is virtually permanent.

We still add the copper washers to the rebuilding kits, as there are some old-timers (some even older than me ) that insist on doing things as original. I can remember a conversation some 50 years ago at Hershey between two long-bearded individuals. One told the other: "as far as I am concerned, when the air in the tires is replaced, the vehicle is no longer original"!

I personally have not used the copper washers in over 40 years, rather using the tip from my friend (gone now, and missed) from Carter.

Jon.

Thanks Jon,

Do I need to pull/drain the carb again to do this, or can I do the 'Blue' loctite in place?

I honestly do not know, but if me, I would pull the carb, and clean the effected areas of any gasoline residue.

Jon.

Going to do the blue locktite tip. Before the rebuild, the engine would start after two rotations of the starter. Now it takes 5 seconds or more and is likely to stall. Now that I have it off again, are there other adjustments I need to make?

After letting the locktite dry 24 hours, took it out today for a drive. Only a small leak out of the bowl, which hopefully the new gasket will swell a bit and seal up. No leaks from any other orifices. I did a very slight adjustment to the float when it was out. So far it is starting and running much better.