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By oldcarmark - 7 Years Ago
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 I purchased this Carb on Ebay last fall. Minimal if any previous usage. Been sitting on a Shelf for awhile. Has the old style Black Bowl and plate Gaskets. Accelerator Diaphragm was flat which I replaced as well as removing the Bowls and blowing out Passages and installing Steel Needle and Seats.and setting Float Levels. I have a 390 CFM on mine now and it runs great so I know the Problem is with this Carb and nothing else. It starts but won't stay running without pumping the Gas. It will run at fast speed but dies as soon as the Pedal is released. Won't Idle to set it up at all.I have set the throttle plates so the transfer slot is just showing so thats not the Problem. I bought this Carb to either install on my Buddies 56 and changing the Distributor or keep it on mine and give Him the 390 which is already setup from being on mine. Any Ideas on what to check before I put mine back on if I cant get this One to work? Thanks
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By charliemccraney - 7 Years Ago
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Vacuum leak, incorrect initial idle mixture setting, or the idle circuit is not working. A way you could check the idle circuit is to spray starting fluid down the carb while the engine is running. If it continues to run with starting fluid but dies when the supply of starting fluid is stopped, then there is an idle fuel problem. Have a fire extinguisher handy.
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By oldcarmark - 7 Years Ago
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I am thinking there is a problem with the Idle Circuit. Mix screws are 1.5 turns out which should get it at least running at Idle. What should I be looking for as far as a problem with Idle Circuit? I had it partially dis-assembled and blew out Passages with compressed Air and used new style Blue Gaskets. Suggestions?
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By charliemccraney - 7 Years Ago
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Take it apart again and make sure the correct gaskets were used. It's real easy to use the wrong gasket and that can cause all kinds of problems.
RE what to look for regarding the idle circuit. Assuming vacuum leaks are ruled out, it's not idling because it's either not getting fuel or air. Make sure the primary throttle blades are actually open and the secondaries are closed. Do the starting fluid test I outlined previously to rule out idle fuel supply issues.
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By Joe-JDC - 7 Years Ago
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The secondary blades should be open and the idle transfer slot should be showing at least .015" -.020". Folks get this wrong all the time. Close the primaries and open up the secondary the correct amount, adjust the idle mixture screws in until it starts to stumble and back out until it cleans up. Adjust idle rpm with vacuum blocked, and primary set screw after you get the idle down with the secondary blades adjusted. You can do that be bending the linkage or by the set screw under the secondary linkage if it has one. Joe-JDC
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By oldcarmark - 7 Years Ago
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Thanks Joe. . I just pulled it back off and put my old one back on the get it running for the Weekend. I just noticed that there are 3 Screws missing that hold the Base to the Body. Holes are threaded in the Body so I I am going to get 3 correct Size Machine screws and fix that. Gonna check the Gaskets that I replaced and make sure they are correct. It will not run at Idle to do any adjustments at all to Mixture etc. I did my 390 CFM Carb so I am familiar with setting the Plates to cover almost all the Transfer Slot.until all U see is a little Square.
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By NoShortcuts - 7 Years Ago
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GooD suggestions and thoughts from all who have spoken-up on Oldcarmark's carburetor problem.
After the suggestions have been pursued, consider reflecting on some less-often-thought-of possibilities. Oldcarmark indicates that the carburetor appears to have had little use when he purchased it on eBay.
Just because something is new, doesn't mean it was problem-free when produced, packaged, and purchased. Occasionally, some of us purchase things longer before we get to use them than we expected. IF when you go to use the item and there's a problem, you may find yourself unable to return it to the point of purchase or the manufacturer for resolving the problem you've encountered, especially if you have misplaced the receipt. Sometimes, too, perhaps so much time has passed that the supplier will not honor the return policy or the manufacturer his warranty.
In some previous threads, Ted Eaton has noted problems he's discovered with new out-of-the-box carburetors he's been provided to work with. My recollection is that Edelbrock produced Carter types have been a problem far more than once.
All kinds of things can pose a problem in the manufacturing or the reconditioning of carburetors. What I've been told more than once is that the metal dichromating process can result in blockages or restrictions in metered passageways.
Again, there may be a reason why the eBay seller listed that barely used carburetor for sale. Too, being barely used, the eBay seller himself may be as mystified as we are why it didn't run right when he went to use it.
The above is meant as something to consider when all the good suggested fixes don't resolve the problem. I've been there myself . . .
Hope this helps. 
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By oldcarmark - 7 Years Ago
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That's something I thought about this Afternoon as I was taking it off (why was it sold ?). It appears to have never been installed as there are no marks on the Base where the retaining Nuts would be tightened down. Who knows. I will look at a couple of things while I have it off and try it back on again.
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By Ted - 7 Years Ago
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I’ll suggest checking the base plate to main body gasket for warpage or inadequate / incorrect gasket seal. Any air leaks at that gasket manifest themselves as an idle problem as the idle circuit must pass through the base plate to main body gasket to get to the engine. Any air leaks at that gasket simply lean out the mixture.
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By oldcarmark - 7 Years Ago
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This Carb. has the smaller Bores which are 1 7/16 Diameter. The bigger Carbs are 1 11/16 Diameter. Can I use the bigger Base Gasket on mine or is that not going to work? I have a couple of new bigger Diameter Gaskets on hand. Can I use them?
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By Ted - 7 Years Ago
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I don’t see an issue with using base gaskets that have the larger than carburetor bore sizes as long as they physically fit the outside dimensions of both the outside of the carb base and the intake or carb spacer. There is a problem in using the incorrect carb base to main body gaskets though as the various internal holes do need to match up. The carburetor kits I use for Holley carbs can come with as many as four different base to body gaskets which makes it prudent in selecting the correct one. Here’s a picture of some of the different carb base to main body gaskets.
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By oldcarmark - 7 Years Ago
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Thanks Ted. I have been working on this Carb for the last couple of Days. Re-checked the Gaskets I replaced on the Plates and float Bowls on both Ends. Checked all the Screws to make sure they were tight. Opened the Secondary Plate a little with the set Screw in the Base.Tried it with front plates completely closed with only the Secondaries open a little. Nothing has made any difference,.It will run with about Throttle half way Open. It does "surge" even then. The problem is in the Carb. I put mine back on and it runs fine. I haven't separated the Base from the Body to check that Gsasket for seal and flatness yet. I will do that before I write this Carb off as being Defective which is maybe why it was sold. Any other Suggestions on what to check?.
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By Talkwrench - 7 Years Ago
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Sounds like something is defective Mark, a bleed hole or something, its not the needle is it? Im sure you would have seen that info Steve posted on how to setup the secondary slots etc ? If everything is right on it and set up properly it will run straight up without adjustment. Second hand carbs are such a risk.. dang!
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By oldcarmark - 7 Years Ago
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Everything is setup properly as far as Throttle Plates adjusted, Float Level, etc . When I installed my 390 which was New it ran right out of the Box. I did have to upsize the Main Jets and setup the Throttle Plates as per Greenbirds Instructions but after that it ran great. This Carb I bought looks like it was never run.Clean inside and out but maybe it was run and couldn't be setup properly and was put on the Shelf. Somethings not right.
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By chris70 - 7 Years Ago
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Does it have manual choke?If yes maybe the small ball in the vacuum channel is missig,or the gasket that holds the secondaries vacuum housing isn't sealing right!That wuold explain the the major vacuum leak,or it's just the gasket between main body and base plate.
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By oldcarmark - 7 Years Ago
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Electric Choke.
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By Ted - 7 Years Ago
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oldcarmark (5/24/2017)
.....Any other Suggestions on what to check?
While this may or may not be obvious, you might double check that the bowl vent tubes are clear. On most Holley 4V carbs, those vents are located on the main body and not on the bowls. The most common cause for the vent tube(s) to be plugged would be a mud dauber plugging them.
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By oldcarmark - 7 Years Ago
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Thanks Ted. I actually thought of that too. Bought a can of spray Carb Cleaner and removed Idle Screws. Sprayed cleaner down the Vent Holes using the included "Straw" and a steady Stream of Cleaner came out where the Screws go. Still working on it.
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By oldcarmark - 7 Years Ago
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Finally figured out whats wrong with this Carb. I contacted a Rebuilder and sent some  Pictures. He knew right away what the Problem is. This 1848 Carb has a 600 CFM Base Plate on it. Either someone messed with it or it was assembled wrong from the start. My Opinion is it was assembled wrong at Holley. It does not look like it was tampered with. Have a look at the Pictures and look at one on Ebay. The 1848 has no PCV Port and only One vacuum Source for Distributor. The Base on mine has PCV and 2 Vacuum Ports. It will never work with mismatched Base and Body. Frankenstein Carb. Anyone need a like new 1848-1 Carb for Parts or put the proper Base Plate on a like new Carb?
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By 57RancheroJim - 7 Years Ago
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Looks like someone butcher together this one, I doubt Holley assembled it with a few slot head screws..
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By oldcarmark - 7 Years Ago
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Those 2 Slot Head were my doing. Missing when I got it.
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By Talkwrench - 7 Years Ago
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Ahhh bugger! 
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By oldcarmark - 7 Years Ago
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Yeah but at least now I know why it would not work properly. I still think this was assembled wrong at Holley. Why would anyone swap the base on a brand new Carb?.
Nothing to be gained. Throttle bores are the same Size. Who knows?.
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By Ted - 7 Years Ago
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Based on the pictures you provided, this doesn’t look like a Holley blunder with the slotted screws that are in place. While it’s possible someone was trying to make this carb have a vacuum port, it’s more likely that the original base plate went on a different carb so that the Ford linkage would be more compatible on that other carb. You don’t show the linkage side of your particular carb but that might help to shed some more light on what you have and why it ended up this way.
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By oldcarmark - 7 Years Ago
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 The Slotted Screws are from my old Teapot. This Carb was missing 2 and the Teapot Ones are same TPI and just a little shorter. If this was someones Handiwork why not put it back together as it wont work with this Base? Complete waste of a new Carb by not doing so.The Linkage on the other Side is the same as what comes on the 8007 390. I trimmed off part of the Linkage using a Dremel to use the Rod and retaining Clip type on my Ford. The correct 1848-1 Base has a Triangle shape Lever which apparently is designed to use on a Ford.
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By Y block Billy - 7 Years Ago
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I also just had a 57 bird come in with one of these 1848 carbs on it and am going through it now, question? how much should the secondary blades be open? and it is also missing 2 screws in the base and I checked another one laying around and it also is missing the same 2 screws, did they normaally come without those?
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