Engine Cuts Out

77 Cj5, Ŧ-176, Dana-300, 304v8

Yesterday my buddy and I were able to get the transfer case out of 2wL, this was a huge win for me!

Now, the motor cuts out while driving. I will say it did this a little while it was in low gear, but it is a lot worse now.

We took a video of it, I am not sure if you can tell anything from the video. I am looking for a starting point. I don’t think it’s a carb issue, I’ve replaced it recently.

Thanks in advance!
https://photos.app.goo.gl/2SVSzksr7aP486dq6

 

It *sounds* like it running out of fuel. Check to see if the fuel filter is clogged, the fuel pump is flowing well, and the float level is set properly. I couldn't tell from the video if it's worse when accelerating. If so, it could also be the accelerator pump. For reference, what carburetor does it have?

All that said, lots of "carburetion" problems are actually ignition problems. It would be worth pulling the plugs to make sure they all look the same, and setting the timing.

 

You can see the the carb below. Did seem to be worse while accelerating. It also backfires a little.
https://photos.app.goo.gl/TmNeABPUS8UDamuJ8

 

Looks like a Motorcraft 2100. I don't have much person experience with them, but others on the forum do. Hopefully they'll chime in.

 

Yes, it sounds like it's way too lean. Could be a big vacuum leak around the base of the new carburetor, or some other vacuum leak.

Sudden stop like that is always loss of gas or spark. Pretty easy to test the fuel system. First, use a vacuum gauge to test the fuel pump. Next look to see if there is fuel at the fuel filter. Then look for fuel in the carburetor. You can look down the carb throat and see a squirt of fuel from the accelerator pump (engine NOT running), or you can take the top off of the carburetor and look for fuel in the float bowl.

A '77 should have the Prestolite ignition. These systems are known trouble. Common failure is you are driving along, and the engine just stops. You pull over, get out, open the hood, walk around the Jeep a few times, close the hood and drive off. Make sure the connectors are clean to the module, and between the module and the distributor. Lots of discussion of this in old posts. site:earlycj5.com prestolite ignition - Bing

What have you done to the Jeep? Any new/old car will probably need the carburetor rebuilt (or replaced, as above), and a complete ignition tune-up. I would not assume that the rebuilt carburetor is set up correctly for that engine.

 

is the fuel filter clogged? we had that issue, new filter fixed it

 

You mention a new carb...same jetting as the old one?

 

I suspect he did not examine the jets. The link shows a 2100, and I would guess it was sold as a direct replacement for the original carburetor. I would also guess that he has turned in to old carburetor for the core charge (bad idea until the carb is thoroughly demonstrated to work right).

 

Lose the Crocs..

 

you are correct, I didn’t know any differently. I was told it was as easy as swapping one for another.

 

Naw, They were in locked in 4x4, lol.

 

i think the formula is if it is backfiring out of the carb it is firing too soon . needs to be retarted. make it fire later. if it backfires out the exhaust it is too late it needs to be advanced. also if it is doing both can be bad valves that don't seat completely. i used to have arrows on my distributor with a plus and minus sign. cause i couldn't remember. another thing i have seen sometime, is that an engine flooding out, can feel just like running out of gas.

 

I've had the same issue with my cj off and on. It has the 4 cyl GM iron duke motor with the original carb (yeah I know not the best motor but it does ok). Found a missing vac cap next to the carb... and wow it ran good after putting 1 on there. Now it won't start without pouring gas down the carb. Gonna do like suggested above. Got a new fuel filter and fuel pump. Hopefully that takes care of it. It's nice weather here so gotta get it going again.