F134 stalling problem?

​Sounds like you're almost there.

 

Follow up. I pulled the top of the carburator and found a lot of debris in the float bowl. I suspect that was causing the float valve to not control flow. I have now installed a filter. I made a pressure tester out of a pressure gauge, a bronze tee and two hose barbs, all 1/4 pipe. Installed it and the pump is delivering 4.9 psi at Idle. Off idle the pressure drops a little but not much. Spec is 2.5 to 3.5 psi per the manual. Tim at Daytona Parts told me to make the float level greater than 5/16 factory spec.
It is running fine now but needs some road testing before I conclude it's fixed. If it acts up again I will install the pressure regulator. Not sure how accurate my pressure tester is as the gauge is an inepensive one.

 

Well still no luck I found a carter rebuild kit number 5145x that has the correct small orifice spring loaded float needle. I even put a fuel pressure regulator on it and set the pressure to 3psi. And it still sputters and pukes out black smoke then stalls after coming to a stop.

 

Not clear to me if you have done a full, systematic rebuild since the initial post.

Is the pump diaphragm good? Idle passages clear, mix screw seat clean? Float is not rubbing on bowl wall, and sticking?

Are the right balls, weights, check valves etc in the right places, and correct??? (Many times they get lost during a rebuild when a carb gets turned upside down.)

 

Have you looked down the throat of the carb while it's behaving this way? You should no be able to see any liquid fuel.

 

Idle mixture screw should be not much more than 1 3/4 turns out. Idle RPM should be about 650-750. Idle vacuum should be between 15 and 20 inHg.

 

I found another Carter YF 938 SD off a F134 when I pulled it apart I noticed the pump check valve has a needle on the end. And the current Carter YF on my jeep has a weight and a check ball. Both carburetors are identical. Except the new carburetor looks like it has never been gone through. Could I have the wrong pump check valve? Because the Hygrade kit I bought has both the needle type and ball bearing type weight. And when I first rebuilt the original carburetor it had the check ball but it was clear that someone had been through it before since it had the rubber tipped nonspring loaded float valve.

 

"Install the pump discharge check ball and weight.
Make certain that the pump discharge check ball seats properly.
Fill the pump discharge passage with gasoline. Use an oil can and clean gasoline.
Fuel should remain visable in the passage above the discharge check ball for 60 seconds.
If the ball check does not seat satisfactorily or if the discharge ball or seat appear damaged,
form a new seat by tapping on an 1/8" stainless steel ball with a 5/32" brass drift and light hammer.
Remove the stainless steel ball and insert new 116-25 aluminum ball. Do not tap on aluminum ball.
Then install retainer ring. Make sure discharge check ball seats in casting as a leak at this point will result in poor acceleration."

 

Well the problem is solved. It no longer stalls out. When I was comparing the two carter 938SD carburetors. I noticed the one that came on my jeep had a metering rod that had 75-996 on it and the other carburetor had a metering rod with 75-1500. I did some research on found out the metering rod with 75-996 was from a Carter SA. I found the info here http://www.earlycj5.net/forums/archive/index.php/t-54657.html I also replaced the check weight with the new one that was in the kit and went on a test drive and it never stalled or smoked horribly.

 

wow, what a PITA. awesome that you not only fixed it but pinpointed the exact wrong part.

 

That must feel good!

 

Congratulation for fixing your problem - I'm still trying to fix a Solex that idle ok but hesitate off a street corner (when warm) and runs terribly when cold

 

Good on ya!

 

Glad you won it over. Fixing instead of replacing is a great learning experience.

 

Congratulations!!don't it feel good when you finally conquer another problem !Never know what somebody else done before you got it.

 

I read a post earlier about pertronix ignition rings being made with the alignment marks backwards?

 

Good info here! I have several 938SD's gathered up that I plan to try and make one good one out of. Scary though, how many years it's been since I tore a carb apart.