I will have a few questions along the way. Just a place to consolidate them:
Some of the parts are encrusted in white crap that I don’t recall seeing on other carbs I’ve had apart. For example...the check ball inside the accelerator pump aluminum assembly. Also the check weight in the top of mid section of the carb. I presume remnants of ethanol perhaps?
I pulled everything apart and boiled the three main body sections in a heavy solution of dish soap. About an hour. This definitely softened the crud somewhat. I also have a paint can full of lacquer thinner for carb soaking, but wondering if some sort of acidic substance might be needed for this.
Some call it white rust. I believe it's called zinc oxidation. I have a YF that is/was in horrible shape that I (a novice) am trying to salvage for the experience. Before and after pictures. Cleaning still in progress. I used Evapo-Rust for the first time. It's slow acting. Mainly for steel and cast iron. It DOES react with the pot metal in the bowl and air horn but it's slow enough to keep an eye on. If you have to be patient and let this stuff work. I would not use it on light corrosion. I knock it off with a Scotch Brite pad.
Lacquer thinner is great for cleaning up oil and grease. It is quick drying.
Last edited by buoymaker; 06/01/20214:00 PM.
"Adding CFM to a truck will only help at engine speeds you don't want to use." "I found there was nothing to gain beyond 400 CFM."
I glass-bead the surfaces with ultra-fine beads and low pressure; THEN send the zinc alloy casting to a metal laundry company to re re-chromated.
All zinc-alloy carburetors will have this problem, Carter and Rochester seem to have it more so than Holley, Stromberg, or Zenith.
Jon.
Good carburetion is fuelish hot air The most expensive carburetor is the wrong one you attempt to modify. If you truly believe "one size fits all," try walking a mile in your spouse's shoes! The Carburetor Shop
I found that hard white stuff plugging up the metering jet on my Rochester. The jet is brass so I don't think it's "rust". The jet was restricted leading to an over-lean condition. I had to clean it out with a welding tip cleaner.
The exploded drawings I’ve seen do NOT show a double spring on the pump arm above the metering rod. But my carb has two. One spring inside the other. Keep the two or go with one?
The plating finish protects the metal from corrosion and oil/fuel staining. Other than that, no. Some paint them. I don't know if the paint eventually chips or falls off. I go natural or as is.
"Adding CFM to a truck will only help at engine speeds you don't want to use." "I found there was nothing to gain beyond 400 CFM."
That’s a good thread you linked. Did not fully understand the metering rod adjustment the way it was explained there. Also was not aware that the jets are common and easy to get.
The diagram shown above shows the metering rod resting on the bottom of the casting while the diaphragm is sitting above the bottom of the vacuum chamber. And that isn't quite correct. If the diaphragm is up in the chamber, the thinner part of the metering rod ought to be inside the jet and not on the bottom of the casting. The adjustment is made like this: Press on the top of the diaphragm shaft until you feel it bottom out in the vacuum chamber (or when the clip stops travel by hitting the top of the bonnet). Then push down gently on the metering rod. It should bottom out on the casting at the same time the diaphragm rod bottoms out. You'll get the feel for this. If it bottoms out first or if it doesn't bottom out soon enough, bend the lip on the metering rod arm to adjust it. If this isn't clear, please advise. The key is: on the bottom of the diaphragm there will always be manifold vacuum when the engine is running. If that vacuum is strong enough to overcome the pump diaphragm spring (the large spring), then the diaphragm will be sucked down in the chamber. It may be sucked all the way down or it may only be sucked part of the way down...depends on the amount of vacuum present and also on the mechanical limitation (more on that in a moment). The adjustment procedure assumes you have idling vacuum and that will be strong enough to suck the diaphragm all the way down. At this point the thick part of the metering rod will be inside the jet...giving you a more lean mixture and the rod will have bottomed out on the casting...that's the point of the adjustment. Getting both to hit bottom at the same time. Then when vacuum drops (engine under load), the spring will pull the diaphragm up and the thinner part of the metering rod will be drawn into the jet making the mixture more rich. This can and will happen without any mechanical movement of the accelerator pedal. Or if you mechanically move it...by pressing on the gas pedal slowly enough not to make for a lower vacuum situation but just to slowly increase speed while keeping vacuum constant, then the metering rod will be mechanically drawn upward...also enriching the mixture because you'll need that to maintain speed. So in the high-speed circuit, the vacuum might be enough to suck that diaphragm down, but the linkage might be keeping everything up. And in the low-speed circuit, you might be lumbering along at 20 mph, come to a hill but never ever change the accelerator pedal and still have the power circuit kick in when your engine vacuum drops to the point where the large spring takes control of your diaphragm/metering rod. This will simultaneously squirt some raw fuel into your throat, too. The upper spring is sort of an absorber on deceleration and also on acceleration it acts to delay things a bit.
~ Jon 1952 1/2 ton with 1959 235 | T5 with 3.07 rear end
Re-chromating the zinc alloy castings is done for protection, eye appeal is a secondary function. Painting is another option, but should be done ONLY AFTER the chromate procedure is done; else there is no protection.
Carter used several different springs, both singles and pairs. A generic diagram is going to be wrong on most carburetors.
ALWAYS go by the part number.
Jon.
Good carburetion is fuelish hot air The most expensive carburetor is the wrong one you attempt to modify. If you truly believe "one size fits all," try walking a mile in your spouse's shoes! The Carburetor Shop
I had separated all the small parts into mason jars of mineral spirits. FWIW, that seemed to dissolve most of the white crap in the needle seat and main jet and what not. Just a bit of scrubbing did the rest.
The main castings are all soaking in a (sealed) paint can full of lacquer thinner since last night. They will get boiled again in a dawn solution here in a day or two.
By the way, I’ve been playing around with my daughter’s rock polisher for cleaning up rusty or tarnished hardware. A scoop of “chick grit” (which I believe is crushed granite) and a bit of water and a day or two in the tumbler can work miracles.
I had previously messed around on some random rust bolts testing various media. The chick grit seems to work about the best for cleanup. I think a guy could do some fancier polishing with finer material, given some experimentation and time.
Parts from this carb like the choke/throttle bracket and the lower pump arm linkage were fairly rusty and come out with a nice clean satin finish. I also did the screws that attach the body together.
Thanks...good to know. We used to give that to chickens to help them digest food. Didn't realize they used it to polish rocks, too.
Well, it’s just something I had on hand. Because we have chickens and it does help them digest food.
I just “repurposed” it on a whim. Worked a lot better than any of the purpose-made stuff that came in the kit with the tumbler. Also worked better than clean play sand from the kids’ sandbox.
jw51 That dual spring set-up is a duration system on your pump I think. Made so when you put the hammer down that solid slug of fuel will be metered out to your carb throat while accelerating.
jw51 That dual spring set-up is a duration system on your pump I think. Made so when you put the hammer down that solid slug of fuel will be metered out to your carb throat while accelerating.
Between your explanation and Jon’s of that YF design feature got me thinking.....
I’ve always thought the B had kind of a “rubber band” feel to acceleration and deceleration. Like the pendulum swings too fast one way or the other.
For those with experience with both carbs, does the YF transition more smoothly in that regard?
The YF is better in that regard. Having said this, I will add the Rochester design wasn't entirely bad with their thoughts on idle/off-idle scheme. But that one fairly good idea wasn't enough by a large margin. It reminds me of a line in "Support Your Local Sheriff" where James Garner asks why there's a big dent in his badge. Harry Morgan's answer was "oh, that's where the other sheriff we had got shot." And Garner says "so this badge saved his life?" To which Morgan replied "well, it would have if it hadn't been for all those other bullets flying in from all over the place."
~ Jon 1952 1/2 ton with 1959 235 | T5 with 3.07 rear end
Should the check weight in the upper part of the bowl casting come free just with gravity or is something else there to retain it?
Seems rather immobile despite all the soaking in various chemicals. Thought about applying some strategic heat but will not do that without someone much smarter than me advising it.
Likewise with the check ball in the pump casting piece. It is still partially encrusted. I see a ring there to retain it. But not sure if that is designed to be removed.
Aside from those two issues, things are cleaning up pretty nicely.
The check ball in the pump bonnet can be removed, however it isn't easy and I've never been certain it was designed to be removed. Patience and cleverness are the keys. The problem is in removing the retaining ring without destroying it, honestly speaking. It is a press fit in there and there are 4 tiny bumps which stop the travel once it is pushed back in. If you want to do this, I'd suggest getting a very small crochet hook or hooked type dental pick and working ever so carefully around the perimeter. There will be a post from one side to the other (diametrically). Alternatively you might use a toothpick with the sharp tips removed. Push down on the ball from the top and see if you can get any motion doing that. You might tap lightly on the toothpick to do that, also. The truth is the little piece holding that ball in place is thicker than you might expect, but it can be bent and damaged. I'd guess yours might be 1mm thick. Replacing it is easy, obviously. As for heat, probably not. I don't think that would help in this case.
As for the check ball, yours might not be a ball but a brass piece that looks much like the needle in the needle and seat (only smaller). Once again a dental pick (straight) or any sort of rigid thin rod (music wire or possibly even a paper clip straightened) might be enough to dislodge it. Once free it usually will fall out when you turn the body over. If yours has the weight and ball...same thing. You need to try to gently free the weight and the ball should follow. When they're stuck like this I clean them up using a common bamboo skewer or small dowel pin sharpened like a pencil or some other round piece of wood which can be made sharp on the end. Get some polishing paste (MAAS, Flitz or Semichrome), put a bit on the sharpened tip of your bamboo skewer and rotate it down inside the hole until you see the "seat" is nice and smooth. A jeweler's loupe is helpful here. I realize not everyone has one of those, but they're very handy. Get a cheap pair of sunglasses or better yet reading glasses, poke out the lenses and you can fit your loupe in there and secure it. I use mine on my left eye, but that's because in watchmaking I always left my dominant eye free to look around at a distance. Years ago I had one which was very solidly stuck. I poured a penetrating oil in the hole and left it for a couple of days and that helped. Think I used Liquid Wrench. I wouldn't waste my time with P T Barnum Blaster, but I understand some people like it...and it might work ok. It seems to me to be another over-marketed and under-engineered product. Kroil used to be good, but I've heard it has changed now. Good luck. Keep us posted.
~ Jon 1952 1/2 ton with 1959 235 | T5 with 3.07 rear end
I suspect this is the check needle rather than the weight ball. I actually thought about doing some gentle tapping with a brass punch. Things “look” a lot better in that passage, but I suspect the white crusty stuff is still cementing it somewhat.
Edit: on the other hand, I can still “see” some of the stuff cementing the pump Bonnet check ball. I’ve been pretty conservative about picking at it. Might have to get slightly more aggressive.
Finally got both the check weight and the pump check ball freed up. A combination of picking with very fine tools and light tapping with a hammer from the back side made the difference.
1) Most likely going to re-use the all metal needle that was in the carb along with the existing seat. They look in good shape. I just bought a cheap kit for gaskets and pump, and I will do some measuring, but sounds like it’s highly unlikely they provide the correct needle and/or seat. Will upgrade to a Carbking kit if we can prove this is a functioning unit.
2) I didn’t have time to study closely, but it looks to me like the metering rod might not be perfectly straight. If so, should I try to carefully straighten it...or am I likely to make it worse? (Or perhaps it’s not supposed to be perfectly straight). Might have been my imagination.
Had to do a bit more cleanup on some hardware last night, but I think she’s pretty much ready to slap back together. If and when I can find a few minutes. Kids’ baseball/softball schedule is gonna start kicking my butt soon.
Incidentally, this project gave the the chance to test several different home-brew cleaning methods:
1) Boiling for an hour-ish in strong solution of dish soap (twice) 2) Soaking for a day in a paint can full of lacquer thinner (my previously preferred method) 3) Soaking in a 50/50 Pine Sol/Water solution for a couple hours. Internet instructions vary on this. Heat is sometimes applied and it can discolor carbs pretty quickly if left too long. I brought it up to a simmer and then shut down the grill.
None of this was in anyway scientific, but it looked to me like the short dip in the Pine Sol might have done the most good. It really worked loose some of the muddy-looking crap at the bottom of the bowl. For some reason, the lacquer thinner didn’t even touch that stuff. And while I wouldn’t take a bath in it, surely a bit healthier to use than the thinner.
Not mentioned was plenty of scrubbing with mineral spirits or cheap spray carb cleaner, lots of compressed air, etc. This post was just about the various soaks I did.
Pine-Sol is an interesting choice! And leaves it smelling like a high school locker room, too, I'll bet. If you are concerned enough about the loss of coating to want to paint the outside (outside only), here's what I did on one YF which had been dropped and suffered a crack (which I had to silver solder to repair): First I masked and painted with Rustoleum Champagne Mist. Left masked and let that dry for a couple of days and then overcoated with VHT Clear Satin. The Champagne Mist color is ok on a carburetor. It doesn't have the iridescent appearance the original plating did, but no spray I've seen does. Some claim to, but in my opinion they just look like an odd mistake in combining gold and green paint that won't mix together well---sort of like Rainbow Brite got sick and threw up. There will be some complex instructions on the VHT can about how you have to treat that stuff at varying and specific temperatures. I didn't do that. I was mainly looking for something clear that wouldn't be affected by gasoline.
Ok, about the metering rod...I'd try to straighten it as best as I could. Lay it on your kitchen counter top where the round end and flattened part hang free over the side and roll it lightly with your fingertips to check. When you have it as close as you can get it, you'll feel it rolls straight. and that should be good enough...unless it is bent where it fits into the jet. That is a different conversation, but usually those get bent in the middle. You can also polish it and the jet with a bit of old t-shirt fabric and some MAAS, Flitz or Semi-Chrome polish. You also ought to remove and check your idle jet. Some call it the low speed jet. If you had a bunch of crud in parts of the carburetor, it could be in other passages too. I use either a piece of small copper wire or a piece of music wire and air or spray cleaner. The old needle/seat ought to be fine and will be better than anything that came in the cheap kit.
~ Jon 1952 1/2 ton with 1959 235 | T5 with 3.07 rear end
Good tip on the paint. Do you have a pic of how that turned out?
I’m not really worried about how it looks, but almost all of the original coating is long gone and I’d like a little bit of protection for the bare casting.
I had thought about polishing brass bits, chickened out thinking that if removing even a wee bit of material on a critical internal might affect running.
Both the idle “tube” and the main jet the rod fits into were removed for cleaning in this process.
Side note: Definitely a lot more going on design-wise in the YF than the B. A more sophisticated machine. Really anxious to see how those differences translate on a running engine.
The YF was designed by engineers. The B? Anybody's guess. Jon (CarbKing) makes something like 84 different kits for it. Tells me GM was trying vainly in dart-board fashion to find something that worked better...possibly without offending whoever came up with it in the first place.
Yes, I did save an image or two. One shows my Frankenstein-like repair.
~ Jon 1952 1/2 ton with 1959 235 | T5 with 3.07 rear end
I’ll start with the easy-to-type questions. The others relate to pump and metering rod adjustments.
1) Use a gasket under the needle seat? I don’t remember one being there when I took carb apart.
2) I’m re-using the “original” needle and seat because neither included in the kit is even close to correct (more on that later). The needle tends not to fall freely when you turn the bowl cover right side up. It’s all in good shape. No burrs or rough spots or anything.
I’m inclined not to worry about that. Figure the incoming fuel pressure would move it down pretty easily. Am I wrong?
3) I’m accustomed to having lots of extra parts in a carb kit. But I’m baffled at the number of small circular gaskets that I have no clear use for. Is there supposed to be a seal around the outside of throttle shaft or something?
4) The base gasket covers one hole on the bottom of the throttle body. I’d assume that’s wrong. There’s a carb sitting atop my manifold insulator currently. Not sure whether there’s a corresponding hole in the insulator. If there is, I’d punch a hole in the gasket. If there’s not, I’d “notch” the gasket to provide access to the throttle bore. I should have taken a pic, but figure one of you has already dealt with this.
(2) The correct needle and seat from the bottom should be: gasket, seat, needle, spring, "golf tee".
(3) Question too general on extra parts to answer, but there is no external seal on the throttle shaft.
(4) USE THE GASKET SPECIFIED FOR THE CARTER CARBURETOR, FORGET ABOUT HOLES IN THE SPACER, UNLESS YOU ARE USING A SANDWICH GOVERNOR.
EDIT: The holes in the spacer are for use with the original Rochester carburetor; the Carter gasket will provide the necessary vacuum signal for the Carter carburetor. If using a sandwich governor, you will need to determine what vacuum signal is required by the governor, and then when to obtain it.
Jon
Good carburetion is fuelish hot air The most expensive carburetor is the wrong one you attempt to modify. If you truly believe "one size fits all," try walking a mile in your spouse's shoes! The Carburetor Shop
3) "number of small circular gaskets that I have no clear use for"
Not all kits are the same. One company may decide to sell a universal kit (YF and YFA) that includes extra parts, like the circular gaskets, even though you don't need them for your carburetor. It may not make sense to us but for the manufacturer and retailer, they have to pay inventory tax and have shelf costs on the number of kits they have. Sometimes it's just cheaper to include a few gaskets that only cost them pennies so that they can have one kit to cover many applications. It's for the carburetor rebuilder to know what and what not to use.
I use the original Carter spec sheet information (specification and adjustment sheets) that Carter produced for that model carburetor (example YF2100s). All the parts that make up that carburetor are listed. When it doubt, check it out.
"Adding CFM to a truck will only help at engine speeds you don't want to use." "I found there was nothing to gain beyond 400 CFM."
(2) The correct needle and seat from the bottom should be: gasket, seat, needle, spring, "golf tee".
(3) Question too general on extra parts to answer, but there is no external seal on the throttle shaft.
(4) USE THE GASKET SPECIFIED FOR THE CARTER CARBURETOR, FORGET ABOUT HOLES IN THE SPACER, UNLESS YOU ARE USING A SANDWICH GOVERNOR.
EDIT: The holes in the spacer are for use with the original Rochester carburetor; the Carter gasket will provide the necessary vacuum signal for the Carter carburetor. If using a sandwich governor, you will need to determine what vacuum signal is required by the governor, and then when to obtain it.
Jon
1) Good.
2) I got it right!
3) I guess they just provide a crapload of seat gaskets? Or perhaps some are meant for parts of an auto choke carb?
4) I wasn’t as concerned about the spacer holes as I was the hole in the Carter’s throttle body that is blocked by this particular gasket. I bought a cheap Walker kit, and if they can’t get the needle/seat right, I have a fairly low level of confidence that they got the gasket right. Idea here was minimal investment (basically replace pump and gaskets) because I wasn’t sure how this core would clean up. Then, upgrade to to a proper (likely Carbking) kit once I have proven it functions.
Side note: I had a fair bit of conversation offline with the other Jon, Jon G, about the incorrect seats, wrong orifice sizes, etc etc. But I’m from the Show Me State and have to see things for myself sometimes. Even though I ordered the “correct” (least wrong) Walker kit....I can validate that none of the supplied stuff would match what came out of the carb. I did measure the orifice best I could with a drill bit. What was in the carb matches what Carter spec’d for the 2100. Both of the supplied Walker seats have an orifice significantly larger.
See attached pic of Carter pump adjustment instructions. To get the metering rod arm to touch the pump arm only at the far edge...I assume I have to “widen” the angle of the external linkage?
Clearly I don’t have the proper Carter tool for this job. Just wanted to see if understand what they are advising here. Presently, the metering rod arm comes pretty flush/ parallel to the pump arm when I bottom out the pump shaft.
Good carburetion is fuelish hot air The most expensive carburetor is the wrong one you attempt to modify. If you truly believe "one size fits all," try walking a mile in your spouse's shoes! The Carburetor Shop
Quote "(3) I guess they just provide a crapload of seat gaskets?" End quote
Some 40 years ago, we started adding gaskets of different thicknesses on OLDER carburetors with cast brass float arms. The cast brass arm can normally be bent ONCE; the second bend generally results in a "two piece arm".
Possibly Walker, or others have picked up on this.
Not necessary with this float.
Jon
Good carburetion is fuelish hot air The most expensive carburetor is the wrong one you attempt to modify. If you truly believe "one size fits all," try walking a mile in your spouse's shoes! The Carburetor Shop
