Bad running 304

[nico]

Hi folks.
My brother has got a cj7 with 304 engine. But there is something wrong with the machine. When Idling the engine running grate, but once he starts to drive there is no power and he has to pump the trottle to get it running. There is zero power in the engine, It is put on a new Edelbrock performer intake and a carburetor in the same brand. The inntake are non egr , and there is just one vacuum hose directly to the distribuater . Is there anyone here who has any tips.

[tufcj]

Was there a problem before the carb/manifold swap, or did the problem start when the new carb/manifold were installed?

If it started with the new carb/manifold, what size is the carb? Is the carb new or used? What gasket did you use under the manifold? Are all the vacuum lines hooked up (PCV, power brakes)?

Sounds like a vacuum leak to me.

Bob
tufcj

[nico]

Last owner said the car was just fine with the original intake, the problems came when he put on the new intake and carburetor. I have a suspicion that he would be lying to us. We have checked all parts of the false air, everything is fine. The engine runs very well until we put it in gear to start driving. It loses the power to start to cough. We have removed the carburetor today to await a new we can try.
I`ts a 650 edelbrock on a performer intake. It runs crappy no matter what we sett the timing at.

[tufcj]

Sounds like the cam may have jumped time. Any idea how many miles on it? Some V8 AMC motors of the era had a synthetic top gear that would break down with wear and age. You might be able to see it by pulling the distributor and shining a flashlight.

Pull the distributor cap and rock the crank, watching the rotor. If the crank moves more than a few degrees before the rotor starts to move, the timing set is probably shot.

Bob
tufcj

[ironman_gq]

Put a vacuum gauge on the engine at idle and see what you have. Should be more than 15" After that check that the accelerator pump on the carb is working and that the main jets arent plugged. It really sounds like your problem is a real lean condition off idle. Does it improve as the engine warms up?

[nico]

Today we changed the carburetor, the engine was running just fine. The "new" 500 carburetor that came with the car is no good. The engine runs just fine now , and this is a 600 carburetor

[ironman_gq]

open up the old carb and make sure the mains arent plugged or one of the air bleads. Most carbs can be fixed pretty easily as long as they arent corroded badly. If its an edelbrock carb everything is pretty visible once you get the top cover off.