engine cutting out

[koeneke2005]

I have a 1979 CJ5 with a AMC 258 i6 / 4.2l and carter carb. The engine Idles fine but when I accelerate the engine starts to cut out and will die unless I let off the gas. If I put my hand over the carb and choke off the air it will rev up just fine. If I remove my hand and rev it up it cuts out again. It will slowly rev up just fine. It only cuts out when the engine is under a load or fast acceleration. Any ideas?

 

[Torxhead]

I would start with checking the accelerator pump in the carb. This can be checked by looking down the throat of the carb w/engine off and opening up the throttle, as you do this there should be two streams of raw gas shooting down into the carb. Sometimes the acc pump diaphram can go bad or the pump linkage can get out of adjustment, refer to a repair manual.

 

[brotherjohn]

Having to put your hand over the carb means your having to "pull" the fuel from the carb by vacuum instead of having it "pushed" from the pump.

 

[koeneke2005]

does that mean fuel pump or carb issue?

 

[Torxhead]

does that mean fuel pump or carb issue?

That would be in the carb, most likely. A bad fuel pump can cause problems also, I use a pressure gauge to make sure the fuel pump output is correct.

 

[koeneke2005]

That would be in the carb, most likely. A bad fuel pump can cause problems also, I use a pressure gauge to make sure the fuel pump output is correct.

Ok thanks for the help. Looks like I might get to do my first carb rebuild.

 

[koeneke2005]

Rebuilt the carb and that was the problem. She runs like a champ. Thanks for all the help!