1954 Carter YH carburetors leak after rebuild

[Peter R.]

[Chuck G.]

Re: 1954 Carter YH carburetors leak after rebuild

You used the wrong kits. You must use the three piece needle valve.

The ones you used are for Corvair and other applications. In addition, often the incorrect lid gasket is supplied with the Corvair kits. That gasket blocks off one of the air bleed holes, rendering the idle mix screw inoperative.

VERY common problem. Not sure who sells the correct kits now. I've been out of the 54 "scene" for 6-8 years now since I sold my car.

Chuck

[Peter R.]

Re: 1954 Carter YH carburetors leak after rebuild

I believe you, but here's a link to the web page for the rebuilding kits I got. http://www.carburetor-parts.com/Cart...Kit_p_627.html You'll note near the bottom of the page where it lists the applications of this kit, it lists the '53-55 Corvette. I guess we can't always trust the suppliers to get it right. I'm going to Carlisle tomorrow and will be on the lookout for the right kits.

Here's an archive thread that talks about the merits of the different type needle and seat assemblies. Not sure what to think.
https://www.forums.ncrs.org/showthre...recommendation

[Peter R.]

Re: 1954 Carter YH carburetors leak after rebuild

Maybe this will help someone in the future. I took the bowl covers off of all three carbs this afternoon. All of the floats showed significant resistance to rising from their fully-down position, i.e., they likely stuck in the full down position, allowing the bowls to fill with fuel and overflow through the bowl vent into the barrel of the carb right at its inlet (a lot of which poured out of the air cleaner). In addition to a vertical component of force that pushes upward on the needle when the float rises with the fuel level due to buoyancy, there is a horizontal component of the force exerted on the head of the needle by the raised tang on the float arm. This horizontal component is causing the needle, which is already slightly cocked in its bore, to jam. If you look closely at the picture you can see that the needle is already cocked even when there is no force on it. When force is applied by the float's buoyancy, the sharp edge on the head of the needle doesn't help, as it tends to resist the needed sliding action between the tang and the needle head. The fact that this needle and seat assembly is longer than the 3-piece assembly that was in the carb, changes the geometry in a way that increases the horizontal force on the needle. The totally different design of the 3-piece assembly doesn't appear to be as susceptible to cocking (and jamming) in its bore. I haven't decided on the best solution yet. Gently rounding off the sharp edge on the head of the needle would help. Flattening the tang on the float arm would help. Decreasing float drop would help. Maybe a combination of these would be good. Using the 3-piece design would certainly help. There may be other solutions. But what I've seen here might explain a lot of really leaky Carter YH carbs.

[Chuck G.]

Re: 1954 Carter YH carburetors leak after rebuild

For decades, those "incorrect" kits were listed as being applicable to 53-5 Corvettes.

IMHO, regardless of what you try, nothing is going to work and solve your leakage problem till you get the correct 3 piece needle valves.

Then, make sure you use the correct lid gasket. Most kits have 2 of them, one correct for Corvette, one not.

After that, I would worry about the floats rubbing the sides of the bowls, the float drop, etc.

The adjustment of the metering rod is also critical.

Used to be that Grossmueller's sold the correct kit for Corvette carbs. I'm not sure now.

Chuck

[Chuck G.]

Re: 1954 Carter YH carburetors leak after rebuild

https://www.forums.ncrs.org/showthre...arburetor+leak

[Peter R.]

Re: 1954 Carter YH carburetors leak after rebuild

Chuck,

Thanks for all the help. You are probably right. But I made another try today with what I have to work with. I installed the wire clips on the needles, which I had previously left out because they didn't fit my floats the way I thought they should and I was going to rely on gravity to open the needle valves. But I got the clips fitting well enough today and could see that they not only help pull the needle down (opening the valve), but also help push it up (closing the valve). It wasn't easy to find clips from my collection (new and old clips) that didn't unacceptably stiffen the needle movement, but I was satisfied in the end and it looked like the clips might prevent the needles from jamming open. So I put the covers (with float, needle, and seat) back on the carbs, tightened the fuel lines, and cranked the engine. After enough fuel got to the bowls, the engine started and seemed to run well, with no leaks, until the bowls filled after 10 seconds or so, then overfilled and overflowed, causing gasoline to spill out of the carb inlets, again. Problem not fixed. At this point I'm willing to invest in three new rebuild kits (after spending almost $100 on the first three kits), if they appear to have better seat and needle assemblies. I was at Carlisle yesterday and visited Grossmueller's. They had rebuild kits on the table and I looked at one closely. I'm pretty sure the needle was the ordinary one-piece brass, Viton-tipped variety. So it doesn't look like that's going to be an improvement. To be clear about the needle and seat assemblies that came out of the carbs, I've attached a picture. I don't think this is the type you have been referring to, but they did work before the rebuild. I would even put these back in, but lost one of the springs during the rebuild process, so I have only two complete old assemblies. Does anyone have one of these lying around?

[Chuck G.]

Re: 1954 Carter YH carburetors leak after rebuild

This is the "three piece" needle valve you need.

The needle valve is hollow. Into that hollow space goes the "pin" and the spring.

[Peter R.]

Re: 1954 Carter YH carburetors leak after rebuild

So does anyone know who still sells this variety?

[Tim E.]

Re: 1954 Carter YH carburetors leak after rebuild

Pete - I checked with Ernesto Gonzalez, an NCRS member who specializes in '53 to '55 6 cylinder carbs here in the Houston area. Ernesto sells the correct spring loaded needle rebuild kits for $52 including shipping. He can be reached at vettecarbs@sbcglobal.net (tell him Tim referred you!). His complete rebuilds are a work of art and NCRS correct.

Good luck! Tim

[Peter R.]

Re: 1954 Carter YH carburetors leak after rebuild

Thank you, Tim. I'll get in touch with him.

Pete

[Peter R.]

Re: 1954 Carter YH carburetors leak after rebuild

To close out this thread I want to add how I was finally successful in rebuilding my carburetors. I got a second set of rebuild kits. This time I got them from Paragon (I tried Ernesto, but the timing didn't work out). I have to say that I was quite happy with these kits--they have the spring-loaded needles that I was looking for, just like those used originally in these early Corvette carburetors. Also, they came with written procedures (complete with illustrations) for synchronizing the throttles, adjusting the throttle linkage across the three carburetors, setting the throttle stop screws and idle mixture screws, and setting the floats (the float settings were a little different from those found in the 1954 Chevrolet Service News). Also, unlike most rebuild kits intended to fit multiple variations of the same carburetor, these kits were tailored to the '53-55 Corvette Carter YH carburetor, i.e., there weren't any leftover parts after the rebuild was complete. The kits had only the parts needed to rebuild the Corvette carburetor. Kind of refreshing. I completely rebuilt the carburetors using all the parts from the new kits. After reinstalling the finished carburetors, I got the engine started with very little trouble and NO LEAKS!! I would say that the 3-piece spring-loaded needles were the main difference that led to ultimate success. Thanks to all for the good advice here on the forum.

[Chuck G.]

Re: 1954 Carter YH carburetors leak after rebuild

Glad it worked out for you, Peter.