1 barrel to 2 barrel 4.2 conversion

[twosport]

Just starting to get my 78’ CJ5 running after sitting for a few years. Fuel makes it to the carb but not into the jets and throat. It will start and run when I pour fuel into the carb but then dies because it’s not getting any fuel. I’ll try to remove it if I can figure out how to disconnect the throttle cable lol and see if I can clean it a bit. BUT, if it needs a rebuild, I think I would rather just go ahead and upgrade from the 1 barrel to a 2 barrel. Questions:
1. Will the original work on the new Weber WK550-38
2. Any idea what might be preventing the fuel from going into the carb. I verified it is going to the carb.
3. How do I disconnect the linkage on the original carb
4. I know I need a manifold adaptor but are there any other things I should know?
5. Guess I can just go to Weber and ask the same questions.

 

[lutry]

Before you go for a Weber, maybe look at this:

New Motorcraft 2150 Jeep AMC Eagle Pacer Carb Upgrade 258 4 2 1 08 Venturis | eBay

I have to admit that I did not buy this, but this carburetor is stock on my AMC 304
and it is very easy in terms of handling and use.

 

[Hedgehog]

You could easily have a stuck float valve. Try tapping on the float bowl or better yet open the carb up and visually inspect the float. You can do this without removing the carb from the engine. Carefully remove the float, make sure the needle is free to move. You are going to find stuff floating around in the bowl. A little is normal, a lot is not normal.

 

[Torxhead]

Another possibility for not getting any fuel into the engine would be a bad fuel pump or clogged fuel filter.

 

[elwood blues]

As much as I LOVE the Motorcraft series carburetors, for ease of use, tech support, and parts availability, you really are better off with a Weber. Yes, it's going to cost you more money. BUT, you're getting a BRAND NEW carburetor, not a "Refurbished" one that some dude is doing in his garage and selling on eBay.

To answer your questions;
1. The original what? Fuel pump? Yes it will work, but you may need a fuel pressure regulator in line between the pump and the carb, Weber's are known to be picky about the fuel pressure.
2. No, the Carter YF 1BBL carb is a POS, that was thrown on these engines because of the gas shortage in the '70s, throw it away and replace it with something else.
3. Throttle linkage? Follow the cable from the pedal through the firewall, there are some brackets that make the cable work with the Carter YF, it's a ball and socket type connector from the cable to the metal bracket.
4. Yes, if you switch from the Carter YF to a Motorcraft 2100 you will not only need an 1BBL to 2BBL carb adapter, you will need a throttle cable bracket of some kind, home made or bought, the linkage from your Carter DOES NOT work with a MC2100. Weber, sells you everything you need in the kit.
5. You could, but we're not trying to sell you anything, and there's a lot more of us that have done this stuff already, and with them you're just talking to a "customer service rep"...

 

[IOPort51]

Are you changing the manifold or using an adapter to but a 2 bbl on a 1bbl manifold??

 

[graycj7]

I just installed a Holley 2300 2 barrel on my AMC 258 i6 / 4.2l six using an adapter plate. This thing has some balls now.

 

[Bent]

I just installed a Holley 2300 2 barrel on my AMC 258 i6 / 4.2l six using an adapter plate. This thing has some balls now.

Mine also ran well with the Holley 2300. At least until I would get on a steep hill. I think the jet and power valve location an the 2300 make It a little sensitive to off angle stuff. I like that the MC2100 locates the power valve and jets at the very bottom of the fuel bowl where they are less likely to come uncovered.