The Stovebolt Site Forums The Shop Area Engine Shop Carter YF 964S Carb diagram for 1950 CHEVY 3100

Does anyone have a very detailed diagram of this Carb.. I'm having trouble figuring out how things go together on the accelerator pump

Give this a try........

Good luck,

First insert the diaphragm assembly into the collar with 4 screws. On top of that slide the larger spring and fasten it with the C clip. Then slide the accelerator actuator over that. It should have the metering rod with spring attached. Then slide two springs over the top, push down and fasten with the smaller C clip. When you install this, be careful to guide the metering rod into the jet. Attached are some images for you. Hope they're helpful. Please send a PM or ask if you have other questions.

Please also note & check: When the diaphragm rod is all the way down, the metering rod will rest on the base of the float bowl body. This is important and the adjustment of it should be checked any time the carburetor is disassembled. You can look at the first image above and see an example of this. Diaphragm rod is all the way down (held by the adjustment tool) and so is the metering rod. Questions? Please ask.

[img]https://www.stovebolt.com/ubbthread...umber/14770/filename/20200125_133332.jpg[/img]Thanks for the information. Here is where I'm getting lost..
I ordered! Rebuild kit from mike's carburetor.. Looking at pictures and drawing, it looks like the pump lifter link is directly below the metering rod arm. Once assembled mine sits about 3/4" below. Looking at different accelerator pumps they all appear to be the same... I guess my only choice is to buy a cheap rebuildable carb and take it apart to see what gives..

Looking at your two pictures above, the one on the left, the pump lifter arm is not installed at all. The one on the right, it appears that the lifter arm is installed upside down (if I am reading your photos correct). The small doughnut in view on the right hand photo will sort of seat on top of the slot that the arm drops into when installed. Jon G’s photos do not show the seal (not sure if it is a year thing or how important it is, but you have one anyway). Follow Jon’s directions and photos and you should get it.

Lee.

LeeD,

I was just showing the hole in the lifter arm and how big it is compared to the accelerator pump shaft and the same for the metering arm. The accelerator pump shaft has two area that are turn down to a smaller diameter. The first is where the metering arm is in the 1st picture and the second is about 3/4" below that. Everything I can tell by looking at pictures and diagrams show the lifter arm should be where the metering arm is in the 1st picture and the metering arm sits on top of the lifter arm. A spring sits below the lifter arm and a spring retainer sits in the lower turned down area. I have no part that would keep the lifter arm up where the metering arm is unless I lost something but have no idea what it might be. I was very careful dismantling everything and putting immediately in a baggie so I would not lose anything.

I am hoping someone has rebuilt a carter 945S carb and can help me out..

The rubber seal probably wasn't in the 964s or 965s, but I add it when I rebuild one. The problem with that seal is you must have the metal collar to sit atop it. The purpose of it is to prevent gas from sloshing up and running down the diaphragm arm (the lifter arm)...which will happen. If you don't have that metal collar, you can make one but it is fiddly work. It must be made of very thin aluminum or brass and is just a shade larger than the rubber seal piece but matching it in shape. You don't need to buy a rebuildable carb and you won't find a cheap one unless you're really lucky. As Lee said you have the arm upside down. Some will call that arm the lifter link. I have no idea what Mike's calls it...I have no comment to make about Mike's here. Everyone is entitled to their opinion and can deal with who they want, after all.

Please see the attached...General diagram of YF. The scan in jpeg format is too large to be attached. This is a pdf and I hope you can save & open it. I have scads of images of work done on the YF carburetors...maybe 200 or more.

Part number 28 on this diagram is the pump lifter link. Atop that sits the metering rod arm--part number 25. The metering rod clip will sit flat on early models and at a slight angle on later models. The diagram I showed you earlier shows this clearly. There is a metering rod clip (part 26) which I call the spring. One end of it fits through a tiny hole in the metering rod clip and the spring part fits on the round protrusion on that clip and then it wraps around the metering rod. You can see this in the image below. Once you get this in your mind, it is very simple. Take a look and let us know what is confusing you.

Jon

The 3rd picture is exactly what might looks like when assembled. Can I assume that is the way it should be then?

I have a new old stock 965s here. I'd rather not take it apart, but if there is no other choice, I can do that. Some of the images I've posted are of a new old stock 965s. That third image above ought to show you exactly what your diaphragm collar, springs, lifter link and metering rod clip/metering rod will look like if assembled correctly. The fourth image shows the little metal piece that sits atop the rubber seal...which slides on the lifter arm and is pinched and held in place by the air horn and the float bowl.

Yes, if yours is in that condition, then you can insert the assembly, guide the metering rod carefully into the jet and replace the 4 screws holding it in. Please note: there is only one way the diaphragm housing will fit correctly. The orientation should be obvious. Once you have that in place, then press down on the top of the diaphragm rod until you feel it bottom out. Then with your other hand lift up on the metering rod and feel to see if it goes back to sit on the bottom of the float bowl. If you have the diaphragm rod pushed all the way down and you can still push the metering rod down a bit to hit bottom, then you have to adjust it a tiny bit (by bending). You want the diaphragm rod and the metering rod to hit bottom at the same time. And your metering rod clip and your diaphragm lifter ought to sit parallel to each other...meaning one end should not sit up off the lifter...please see first diagram above.

And when I say by bending, I don't mean the metering rod. I mean the metering rod clip...

Thanks Jon, I think that gives me enough info.. I just thought the lifter arm directly pushed down the pump instead of going down until it hit the spring then pushed down the pump

Actually it lifts up the diaphragm to squirt fuel into the bore...kind of backwards from what most people expect.

OK.. I received the new float and working on adjusting it.. All I've read says to invert the fuel cover and set the float to about 15/32" then turn fuel cover and set the end of the float to 1-1/4". I did all of that but the float hanging down 1-1/4" sure looks way too low to me. But hey, what do I know.. Are these the correct settings for the carter 1 barrel model 964s carb

Adjust to the measurements for your carb

Remove gasket

This is the sheet for my carb. But youll get the idea

...click....

When I set it to those settings the float almost bottoms out in the float bowl.. Is that what it's suppose to be like.. Just seems way too low to me

9/32" inverted and 1.25" on the drop is what I have for the 965s and I suppose they'd be the same for the 964s. Does your new float match the old float in appearance?

Yes.. But my carb is a road yf and I had to buy a type w-1

You just lost me. You bought a W-1 float to use in a YF? As I recall the W-1 is taller and different.

[img]https://www.stovebolt.com/ubbthread...umber/14957/filename/20200118_162702.jpg[/img]Sorry..i bought a rebuild kit that came with a float. The kit was based off the model number stamped on the carb and year/model of the truck. The float looked different than the pictures I look during the dismantle of the carb. I tried using it but just didn't look right when I tried to adjust the float (cant really remember the issue). After some searching I found one the looked like the one that came out of the original carb so I bought it. The second float was for a Carter W-1. It still had minor issues though.. Attached is a picture of the original float.

I see. Was there a problem with the original float? The image you have provided shows the proper one for the YF. Personally I would use that one unless there is a hole in it or a split causing it to leak or malfunction. And please, please be careful with the size of the orifice for the needle and seat. The original orifice for the fuel flow was .081" or a size 46 drill to check it. If you've bought a kit from somebody who doesn't care, isn't well versed or something you could have one of the very large seats and this can cause flooding. If you need them, I think have all or most of the specs for the 965s. I think that little clip is on the wrong side of the float shaft. On that side, the shaft can work its way out...

After I received my rebuild kit a threw away some original stuff instead of keeping it like I should have.. I looked in the kit and seen the new float and figured it was the same.. I guess I learned a good lesson

If somebody sold you a kit for a YF which included the W-1 float (which it is beginning to sound like), you ought to notify them they've sent the wrong thing and ask them to send the correct float.

Just an observation, but the float in the picture you attached is sitting really high.

I think they sent the correct float for the kit.. Was based off the year, make and model of the truck. If you look at all the kits offered for the truck they all have the same float... But the float that was in the carb appears to be from Model w-1.. Not really sure why..

Colton, the bottom line is the float you have shown in the image you attached above is the correct one for the YF964s. It is however badly out of adjustment and will not work until that is corrected. With the air horn inverted and no gasket in place, the float needs to sit 9/32" from the carb body. Then turn the air horn over and let the float hang free. Adjust so that it drops 1 and 1/4 inches (at the outward end). Reverse the shaft holding the float in place. You do not want to allow it to work its way back into the carburetor. That will let your float hang free, your needle will fall out and absolutely nothing will work then. The little retaining clip should be on the opposite side from what is shown in the image above. Good luck.

Please see the attached images. This is how you do it.

Last night I adjusted the float to the specs you guys stated. When Adjusted to 1-1/4" I measured from the horn body to the very bottom of the float, then measured how deep the carb body was. The float hangs and barely hits the carb body.. Ive adjusted floats before so I have alittle experience.