Carb Question

Working on a '74 CJ5. Has the original engine but someone changed the intake to an Offenhauser 4 barrel "carter afb competion series". Runs way too rich but accelerated great. Tried adjusting the idle circuit but still have this problem. Any input would help, money is not a concern. Rather just replace the carb with something that would eliminate this problem. Thanks in advance.

 

Which engine?

 

I'd guess it's a 304. I assume it's an Offy manifold and Carter AFB carb.

If I wanted to keep the AFB, I'd start here:
http://www.amazon.com/exec/obidos/t...f=sr_1_1/104-9881625-2413521?v=glance&s=books

hth

 

Sorry, should have mentioned it's a 6 cyl. 258 cu in I assume.

 

IMO a Carter AFB is too much carburetor for a 258. You need to pick a carburetor with small enough venturis so that the air velocity at idle is high enough for good atomization. With a big carb on a small engine, you don't have any control over the mixture at low RPM.

The easiest route is to sell the 4V manifold and AFB, get a 2V manifold from an 80s CJ, and either use the Redline 2V Weber kit, an Autolite/Motorcraft 2100/2150 2V (junkyard carb), or the Howell EFI. Once you have the manifold, the Autolite can be done for $100-200, the Redline kit is about $400-500, and the EFI is about $1000. Bothe the Weber and the EFI are bolt-on kits; you'll have to do some adapting to use the Autolite.

If you really want to keep the 4V manifold, I think you'll still need to get rid of the AFB. There are a very few 4V carbs that might be ok, but that's a much longer topic (and one that's been hashed and rehashed here).

BTW (moderators) this topic should be moved to the Intermediates forum.

 

Tim, thanks for the input. I feel this is way too much carb for the engine. Sorry to post in the wrong forum.

 

No problem! We have a crew of moderators that go all tingly when they get to do something useful

 

If you want to do EFI, dont want to spend $1200 and fell like playing around a bit, you can go this route.

www.megasquirt.info

forums:

www.msefi.com

I am running this system on my CJ-5 w/258 using a GMC TBI. It works good and I have spent maybe $600 total on it. It is a great DIY project. You can buy an adapter plate that converts your 4 barrel intake to GM TBI. Then is just a matter of the sensors and wiring. The system is tunnable via a computer serial port (desktop or notebook).

 

My Holley 390 is too much carb on my 75 258. I finally have it so it runs sort of OK.

$ being saved for a Howell...

 

Does it run rich ?