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Unread 06-11-2014, 06:55 PM   #1
John Strenk
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National Carb $160.00 BBD replacement review

Well I broke down and bought a NEW carb from National Carburetor to replace the BBD I rebuilt.

Mine was having some problems with the idle and needles popping out of the main jets and hanging up. I think it was too much cross matching parts from different BBD's I have laying around.

So when I heard about EMI's $160 BBD I had to try it out.

I ordered one for a 1980 Jeep 258. My engine is really a 76 258 with a 84 Intake and exhaust. Figured no sense getting the one with the stepper motor if I don't need it. And I have a 1980 motor I'm keeping as a spare.

My old carb would idle at 18 inHg @ 800 RPM when it was working otherwise it would kick and stumble dropping to 15-16 inHg.

Doing nothing but bolting on the new carb gave me 19 inHg at 1100 RPM.

After a little tweaking I got it down to 20 inHg @ 800 RPM.

The only trouble was the throttle stuck after installing the carb. The new carb came with a thinner spacer and the original springs would not pull down the throttle at idle. A new spring fixed that all right.

The original idle mixture screws were about 5 turns out with hardly no effect on idle but it was idling high. Dropping the idle down and turning in the screws to about 1-1/2 out turns made it sweet. Mixture was fully adjustable from rich to lean.



No Carter Name here


Bottom of Venturi matches the throttle bore. The Carter BBD does NOT.



Vacuum and idle speed without touching a thing


Top View. I wonder if they really put these on a dyno as the tag says



Total Itme to remove and install the new carb. 31 min...

Result, I'm happy. It runs without worrying if it's going to keep running past the next stop sign.

Need to run a long term test though. See if I'm still happy next month.

I took videos of the whole install if anyone is interested.....

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Unread 06-11-2014, 07:05 PM   #2
John Strenk
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Final Results:

http://www.youtube.com/watch?v=4tYu...ature=youtu.be
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Unread 06-11-2014, 08:24 PM   #3
Guy Smilie
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Thanks for sharing John. I'm thinking of going to them for a new YF for my Jeep. I would be interested in your install video.
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Unread 06-11-2014, 08:45 PM   #4
LumpyGrits
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John-Did your other BBD have the exposed idle mix screws, like your new one has?
Are you going to do the idle tube mod?
http://home.sprynet.com/~dale02/idle.htm
Nice write up and THX.
LG
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Unread 06-11-2014, 09:29 PM   #5
John Strenk
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The BBD I had on thee was a feedback carb that had the idle mixture screws hidden, The PO had cracked the area away so he could get at them.

I'm going to wait and see how this carb works first.

When it stops raining...
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Unread 06-11-2014, 11:15 PM   #6
BlkCJ7Laredo
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Glad to see these are a good replacement! I just purchased a brand new NOS real Carter BBD pre-stepper from Allstate Carburetor and am anxious to see how it performs when I get my build done. I think I got the last one they had as the site now says "Call for availability" and it didn't say that before I ordered.
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Unread 06-12-2014, 05:56 AM   #7
keith460
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I've been interested in these carbs as well. Been mulling over the idea to replace my current genuine Weber 32/36 with a Weber 38DGS or a Carter type from National Carburetor.

While the Weber 32/36 runs good, it isn't great. A little to small for a 258 engine that is bored 0.30 over but gives decent gas mileage. And I figured since I already have the setup to use the factory air cleaner assembly, I would just purchase a Weber 38 but the fuel inlet is on the other side.

Going back to the stock Carter carb would lower my air cleaner assembly back down 1 inch to where it is suppose to be and I have a stainless fuel tube made for it from the filter to the carb. The tube has a drop loop incorporated into it so fuel is available between long periods of startup. This was always a problem with the Weber carbs rubber hose connections.

Couple of questions:
Is the EMI's a Chinese knockoff of the Carter?
Was it part # ND 2910 that you ordered?
What would be the difference between the ND 2910 for 1980 model year and the ND 2912 for the 1981-1984 model years W/Out the stepper motor?

Just saw your video and will say "God Bless You".... I heard you sneeze I think.
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Unread 06-12-2014, 06:47 AM   #8
Matt1981CJ7
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John,

As you know, I recommend National Carbs a lot. If your BBD is anything like my Q-jet from them, I think you will too.

I also found their customer service to be excellent. They jetted my carb for elevation, for no extra charge. When I installed it, and started tinkering with it, I felt the secondaries were a little rich, so I called National carbs and they sent me leaner metering rods, again no charge.

Also, I do believe they run their carbs on a dyno. Mine had a distinct smell of fuel straight from the box.

Matt
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Unread 06-12-2014, 08:41 AM   #9
John Strenk
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Quote:
Originally Posted by keith460 View Post
I've been interested in these carbs as well. Been mulling over the idea to replace my current genuine Weber 32/36 with a Weber 38DGS or a Carter type from National Carburetor.

While the Weber 32/36 runs good, it isn't great. A little to small for a 258 engine that is bored 0.30 over but gives decent gas mileage. And I figured since I already have the setup to use the factory air cleaner assembly, I would just purchase a Weber 38 but the fuel inlet is on the other side.

Going back to the stock Carter carb would lower my air cleaner assembly back down 1 inch to where it is suppose to be and I have a stainless fuel tube made for it from the filter to the carb. The tube has a drop loop incorporated into it so fuel is available between long periods of startup. This was always a problem with the Weber carbs rubber hose connections.

Couple of questions:
Is the EMI's a Chinese knockoff of the Carter?
Was it part # ND 2910 that you ordered?
What would be the difference between the ND 2910 for 1980 model year and the ND 2912 for the 1981-1984 model years W/Out the stepper motor?

Just saw your video and will say "God Bless You".... I heard you sneeze I think.

I really don't know were the carb was made but I didn't see one of the familiar Carter numbers or ID's cast into the housing. I didn't want to open it up yet...
Usually a knock off will have some differences from the original but these seem like you can just about interchange parts from these to an original.

I watched their video of old carbs being cleaned and tumbled but I doubt if that would of removed the castings. I wonder if you can order a rebuilt Carter BBD from them.

I got the #2910 because I have on old 1980 engine as backup but interesting. It should of had an hot air choke but this one came with an electric choke. My 1980 engine still has the cast iron intake manifold.

I would think that the 81-84 would have the electric choke.

You can always call them and ask.
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Unread 06-12-2014, 05:39 PM   #10
VooDoo2
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Tried to order, wont ship to Australia
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Unread 06-12-2014, 05:45 PM   #11
LumpyGrits
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Quote:
Originally Posted by VooDoo2 View Post
Tried to order, wont ship to Australia
Maybe you should come over and just pick it up
LG
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Unread 06-13-2014, 01:29 PM   #12
John Strenk
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Day 2

Went out to see how it starts...
Started right up but I see I need a little choke adjustment. Not enough choke for a cold start.
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Unread 06-13-2014, 02:32 PM   #13
LumpyGrits
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Quote:
Originally Posted by John Strenk View Post
Day 2

Went out to see how it starts...
Started right up but I see I need a little choke adjustment. Not enough choke for a cold start.
THX
LG
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Unread 06-13-2014, 02:38 PM   #14
keith460
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I just ordered the ND 2912 today for 1981-86 Jeep CJ's.

It was $209.95 without core. After reading their warranty and core return policy, I do not think I can give them my OEM Carter as a core exchange since the ND 2912 is a carburetor without the Stepper Motor. My original is a Stepper Motor model and the core MUST BE exactly what core was sold.

I called them and they confirmed the return core must be of same one sold, no exceptions!
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Unread 06-13-2014, 02:44 PM   #15
LumpyGrits
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Keith-What was the core chg?
LG
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