Help! SBC 350 in CJ2a

Hello. I recently switched carburetors on the 1969 sbc350 in my 1948 CJ2a. I had a quadrajet that needed work, I took it into to get it rebuilt. Instead I bought a rebuilt Carter AFB competition series carburetor. After the old quadrajet sat at the shop for a week, my mechanic recommended the Carter because the QJet was too smart for the engine. So in the meantime of waiting on the word about my carburetor, I installed new exhaust manifolds and a better alternator bracket. The alternator bracket fits nice, and the V belt is tight. I reinstalled the carburetor and I have a problem - The Jeep won't run! It starts rough and dies, backfires most of the time, and has caught fire. I have checked the firing order and it is correct. The jeep ran pretty good before I put the new carburetor and alternator bracket on. I've read forums and they suggest from other people's posts that it is the timing. Well I don't understand what that is or how to check that. If the V belt is too tight would that cause this? How could the timing change all of a sudden? Thanks in advance for the help!

 

Wow, that sucks. I’ve got a Carter AFB too, I’ll try to help you out.
Unless you moved the distributor your timing shouldn’t have changed, don’t see that being the problem.
Sounds like you might be dumping too much gas, make sure a needle isn’t sticking. Since you have to pull the floats out of the way to inspect the needles it would be a good time to check the float height also. There’s an online manual for an Edelbrock Performer carb that is the same thing. I’ll see if I can dig up the link.

 

Here you go, here’s the link.

http://www.edelbrock.com/automotive_new/mc/carbs_acc/pdf/carb_owners_manual.pdf

The relevant section for float height is on page 8.
And just a piece of advice but if you’re going to run a Carter AFB on a Jeep motor you should buy a pair of off road needles, if yours doesn’t already have them. They’ll be spring loaded instead of rigid to help absorb fuel slosh when bouncing around trails.

 

Ok thanks for the advice. I ordered the off road kit, and I'll check out the float height while I'm waiting on the kit in the mail. Appreciate the help, I'll post the results!

 

Please do.
But I do have a question, WTH is your mechanic talking about with this “carb is too smart for your motor” stuff?

 

The Qjet was a 1986, and it had some extra options on it for a computer. The motor is a 1969, so no need for all the extra "ports" sticking out of the carb. I couldn't find anybody to rebuild the Qjet. After the Qjet sat at the second mechanic's shop for another week, He opted that I go with the Carter AFB Comp series, which he explained is really the same thing as a Qjet, minus the extra computer stuff. It looks an awful lot like it, and looks like it'll be easier to tune. I don't know hardly anything about carburetors, so I might have got hosed. The mechanic seemed genuine and had some impressive vehicles at his shop. He had a camaro in his shop that he equipped with a 1,000 horsepower, and also a mazarati. I explained the carb would be used offroad, and he said the Carter is an awesome carb, and it'll work great. I like the Qjet, and if the Carter is the same thing, but easier to tune, I decided to give it a shot. Any suggestions?

 

A Carter AFB, and it's Edelbrock Performer equivalent, are good hotrod carbs but they're referred to in the Jeep community as Edelflood because they don't operate at angles very well.
As far as tuning unless you've got some serious mods to your engine the base jets and emulsion needles will work just fine. You should be able to just bolt the carb up and go, might have to fiddle with the idle mixture screws to get the best idle out of it but that's about it.

 

There is a chance the float needles are his problem but I would still continue looking for a root cause while he's waiting for the off road needles to arrive.

Traveller, if I were you I'd go ahead and break the carb down. Clean it all up real good with carb cleaner and take note of the primary and secondery jets sizes and the number on the side of the emulsion needles, the color of the emulsion needle springs would be nice too if you can still make it out, then compare that to the base setting listed in manual at the link I posted.

 

Ok Thanks for posting that manual. I guess I'll run this CarterFlood until I can upgrade to a good QJet. I'm almost tempted to tow it to the shop at the end of the street and let them fix her up. I have to take it in for new wheel bearings and lockout hubs next week anyway. That carb catching fire (twice) made me a little skiddish. I appreciate all the help, I'll repost when it's all settled. Thanks

 

Edelbrock has a carb for offroad use. It is designed for the rough rides and angles. Something about spring loaded needles.

EDELBROCK THUNDER SERIES AVS® 650 CFM, OFF-ROAD CARBURETORS

 

If he puts off road needles in his Carter AFB he'll have basically the same thing.
The problem with them is the float bowls on the sides and the way the floats swivel at the back. Climbing a hill the fuel sloshes back, the floats drop out and start dumping more fuel in and it can flood.
Side to side there is a balancing channel at the back of the carb that can allow fuel to slosh to one side or the other while side hilling again flooding the downhill side. This can be corrected to some degree but taking a piece of vacuum hose, just about an inch or so, splitting it in half and stuffing each half into left and right side of this channel. It creates a baffle to help keep fuel in its respective float bowl and from what I've heard you can practically set a Jeep on its side and it'll keep idling with the vacuum hose baffle mod. I've never set my Jeep on its side so I couldn't tell you about that last one though.

 

http://youtu.be/j-_AkOkbSiw

Carter AFB Rebuild part 1 of 6. The rest can be found at YouTube.

 

Thanks Corveeper I'll give the rebuild a shot. I'm almost tempted to just buy a reman QJet. Have you had a lot of problems with your Carter? I'm in Florida, so there's not a whole lot as far as hills go, so it might not be an issue. On the other hand, I don't want this cj2 to have any handicaps.

 

Problems? Not really, just know that on a hill climb if you have to push the clutch in you might as well start planing your route back down because your engine will die.
Otherwise its a simple and effective carb. The one I've got is sitting on top of its third different engine combination, it's easily tuned to each different setup and made great power with crisp throttle response.

 

Are you sure that what you have is an AFB? It's a completely different carb from the Qjet-they look nothing alike. There were some Quadrajets made by Carter back in the 70's, so it's possible to have a Qjet that says Carter on the side...

 

so now I am confused.. which is the best carb for off road use?

 

You changed the carburetor but did you change the base gasket? Each type carb has its own base gasket.

 

Yes I did change the base gasket. It doesn't look exactly like a Qjet, it just has the 4 barrels with the back 2 being larger. But yeah it's definitely a Carter AFB comp series, it says so right up front. I guess it doesn't really look like a Qjet, but to me it looks like pretty much the same thing.