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Carb rebuilt but accelerator pump has issue.


Guest 1930harley

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Guest 1930harley

So thanks to the forum the carb on my car is early 50's. I have a carb rebuilding kit as the accelerator pump is not working. Mechanically inclined but never rebuilt a carb. Is there anything that I should know now before I start taking it apart. Like "watch out for this little spring that shoots across the room" LOL. Does anyone have instructions to make this go smoothly? Thanks for all the help on the previous posts.

Edited by 1930harley (see edit history)
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Hi. Just like you, I was pretty hesitant to rebuikd my card because of the "little spring or whatchamacalit" . Did some research on line - google "rebuilding (your make / model) carburetor" that you have and you should get a listing of how to and documents / sellers of those documents for rebuilding it. Buy a NOS / NORS rebuild kit (again google) and follow the instructions. As you take it apart, use your digital cameral to photograph every step starting with the carb before you take one screw off, and continue to do it until it is fully taken apart. Clean everything with quality carb cleaner (CRC is very good) then follow the instructions provided with the rebuild kit and the documents you may have purchased (they are invaluable..trust me!) Did that with my Carter WGD 2BBL and set it to factory specs on the bench. Mounted it up to the engine and ...ZOOOM. Started right up and idled like it was new. Let me know how it goes or if you have any more questions...good luck! Jim

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Older carbs are pretty simple to overhaul, but a couple of thing to keep in mind, be careful not to dislodge any crap that may have built up internally over the years, as it does'nt take much to plug up the small passages inside of a carb, I use a can of carb clean with a spray tube on it[should come with it] to clear out any passages and clean out the float bowl, and if you have access to a compressor some light cleaning with a blow gun does'nt hurt, also float adjustment is important, not something you should have to deal with, but you will want to take care when taking apart and putting together carb not to bend the pivot arm on it.

Don

1947 56C

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Guest 1930harley

Just an update. Rebuilt the carb and I didn't even have any pieces leftover. LOL. but I am having one problem. One of the reasons I rebuilt the carb was the accelerator pump was not working. After rebuilding the carb the accelerator pump was working for the first few times then stopped. I would assume that I should see gas come out of the jets every time the throttle is opened up? But after the first few times nothing is coming out the jets. I turned off the motor and pumped the throttle but nothing came out of the jets. Where do I start to figure out what is wrong?

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Guest kaycee

Hi,

If the float bowl has gas in it, the problem has to be the 'jets' it squirts out of or a check ball at the bottom of the pump. You may have some 'dirt' left in the carb.

:) kaycee

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Guest kaycee

Another comment, first thing to check is whether there is gas in the float bowl and the check ball at the bottom of the pump is free. If you find no gas in the float bowl ( assumming there's no 'dirt' left in the carb. and float is free and properly adjusted and allowing gas to come into the carb), Try blowing compressed air or carb cleaner through it again. Oterwise, you'll have to check the flow into the carb i.e. filter, lines, and fuel pump etc. Please keep us posted.

:) kaycee

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Most of the accelerator pumps have an override on them (what the spring on the shaft is for) should something in the pump delivery circuit become clogged. Otherwise, if the pump didn't pump, the circuit was "locked-up", it would affect the throttle's ability to work.

The pump feeds from the bottom of the float bowl, with a ball check (as mentioned) being the valve that prevents backflow from the pump's cavity into the float bowl. Typically, though, I suspect the ball check is seating sufficiently good to prevent significant backflow . . . unless that area was highly pitted for one reason or another. Some of the earlier rebuild manuals mentioned taking a small punch, along with a hammer, and striking the existing ball check as it's in its seat, to make sure the seat is in good shape (reshaping it in the process), then discarding that particular ball check as you'll have a new one in the rebuild kit anyway. YET, I seldom saw that being done and, from my own experiences, never saw it need to happen, but I always used the new check ball from the kit.

Unfortunately, you'll probably need to pull everything back apart. With the little run time, you can probalby re-use the new gaskets and such . . . using some finesse where possible in disassembly. With the spray can of carb cleaner, you can check the pump supply hole for being open, then you can (with the venturi cluster removed), check the circuit from the pump to where the venturi cluster is, then visually check the passages in the venturi cluster (the "shooter" jets" before you spray through them. NOW . . .you'll need some EYE PROTECTION during these adventures, for sure, period! Once you spray in the direction of "pump output", then you might also do a "reverse flush" of the same circuits/holes, at least to the bottom of the pump cavity.

Seems like there is another check ball/weight right under the venturi cluster, in the carb's main body. This is an "anti-pullover" valve . . . sometimes a ball check or pointed weight, sometimes something different. This keeps air flow from pulling fuel through the pump circuit as the engine speed increases. It should be free and such. If it's NOT free, it can kill the pump output at that point and be very hard to find out why.

Just some thoughts,

Keep us posted!

NTX5467

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Guest 56 Rum Runner

Several things. First you DO want to disturb any crud that has built up over the years... that's the whole point of rebuilding the carb. Go to the parts store and buy a can of carb dip. It's the same size as a paint can. Disassemble the carb and put the components in the dip bath overnight. Get a couple of cans of carb cleaner, an old tooth brush, a small pick (or paper clip) and a air nozzle on you compressor. Get EVERY bit of material that isn't metal out of the carb. You have to put pressurized air through the small ports and gallies. The smallest bit of crud in an internal passage can make the whole carb act up. While your cleaning everything make sure you soak your accelerator pump in some clean gas. This helps "condition" the leather band and assure it expands evenly. Next... I have had check ball seats that were out of round. When everything is clean put the check balls in; put a small amount of clean gas on top of them. If the gas leaks past them you'll need to reshape the seats. I've never used the method of striking the old ball into the seat to reshape it. I took an old phillips screw driver and ground it down to the correct size then GENTLY, very gently "reamed" the seat. Do this a little at a time. Turn it a couple of times then clean with carb cleaner. Put the balls back in and do the leak down test again. Repeat until no gas gets past the balls. You'd be amazed how the tiniest leak past those balls will affect your carbs performance. Lastly... take your time. It took 50 + years for that carb to get dirty and it'll take some time to get it clean, but if you take your time and do it right it'll be another 50 years before someone has to do it again.

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Guest 1930harley

Thank you all for responding. I wish I knew what carb is was. It has been identified by forumites as a carter from the early 50's. Bob from Bob's automobilia identified it as an early 50's and sent a Daytona parts co kit #109. The check ball from the kit was bigger than that in the carb. I also had my doubts whether the acceleter pump was as big in diameter as the old one. I was hoping it would swell. I did use the gallon of carb clean but only soaked it about an hour. I guess I was worried about leaving it in overnight and starting to pit the metal. I did use lots of carb cleaner and compressed air but did not do the check ball test. I guess I need to find out which kit has the smaller check ball and verify the diameter of the accelerator pump. Now that I know where all the parts go in the carb it is not as daunting a task and will pull it apart one more time. I did put it on the car to see how it ran. It is still misssing at higher RPM. I have done the basic tune up items and still think it is carburation. It's clear the accelerator pump isn't working as it stumbles when throttled but after the stumble seems to run ok when accelerating. It is when I back off at higher RPM that it seems to miss.

I also thought I should share a picture.

post-69583-143138291853_thumb.jpg

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The accelerator pump is not causing a miss at higher RPM's. The value of a properly functioning accelerator pump only lasts at most a couple of seconds. In fact, right after WWII in rural areas, it was common to completely remove the accelerator pump from the carb in order to save fuel!

IF it is the carburetor, it sounds like the carburetor is lean at high vacuum conditions (compression and ignition can cause the same symptoms).

Fuel issues possibly causing a lean condition:

(A) wrong carburetor - identifying the carb is your FIRST issue

(B) improper float setting

© improper jets

(D) improper metering rods/setting

(E) improper vacuum spring

(F) deathanol fuel

It is impossible to check B, C, D, and E without knowing A.

Carter stamped a code number on the underside of most of their non-Chrysler carburetors. To locate this number requires removing the carburetor, and cleaning the underside of the throttle body. Repeat - this is a STAMPED (not raised) number. The metering rods will also have a cast (raised) number right below the eyelet. These two numbers, along with the type (WD-0, WCD, WGD, etc) will identify the carburetor to within one or two possible. Certainly enough to determine applicability and settings.

Jon.

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Guest 1930harley

On the underside of the Carb is stamped 006 or looked at from the other direction is 900 opposite that is a stamped S. Will get metering rod info later today and update thread.

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If the engine seems to miss at higher rpm with a suddenly-closed throttle, that could well be another issue all together, rather than a high-speed miss "under load" or "cruise".

For general principles, make sure the COIL is hooked up with the correct polarity for the charging system. If it's not correct, it can result in a weak spark, which can (as mentioned) cause performance complaints highly similar to carburetor issues.

For additional diagnostics, I'd run the engine for a good while (to make sure everything's working smoooothly and correctly . . . with NO missing), take the rpm up for a little bit, stabilize it for about 30 seconds, then suddenly close the throttle to trigger the missing situation. Then, kill the engine. Carefully remove a few spark plugs and see what they look like. Looking for wet insulators . . . either gas (which you can smell) or oil (which will have a different look and smell) . . . or "normal" light colored. As you mentioned the miss after/during a high-vacuum situation, I suspect it is getting something onto the spark plugs and causing a mild-fouled situation. Just got to figure out the source. Otherwise, a vacuum leak somewhere.

Keep us posted!

NTX5467

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