Need Advice - Carter Carb Flooding Problem

I'm having a flooding issue with a Carter YF92 on my 64 F134 CJ5. Jeep was running fine, then I had a fuel pump failure and installed a replacement pump (NOS dual acting pump model 4032M), similar to the Carter fuel pump that was on it previously. After getting it all back together the engine started up ran fine for a couple of minutes and then died. Found fuel dribbling out of the throttle linkage shaft, which I know from past experience is a clear sign of flooding. Took the carb apart, checked the float (made a slight adjustment to get to 5/16" at full closed) and still had same issue. I had a similar flooding issue last summer which lead to the discovery that the carb was full of gunk. Cleaned it out, installed a rebuild kit and it has been running fine until the fuel pump problem. Side note - I've now had to replace or repair every part of the fuel system not made of steel (carb, fuel pump, rubber hose, fuel tank sending unit float.

I've been searching flooding issues in the forum and I guess first thing I should check is fuel pressure on the new pump. Any other common causes of flooding I should check?

Thanks in advance for your help.

 

Yes. The YF is sensitive to over pressure.

Also regarding float height settings, there are different specifications for different float valves. Jeeps were supposed to have valves with a smaller orifice to reduce the force on the float, for "rough service." Some needles are sprung, others are not, etc. Not all carb kits have the correct parts, and not all are set properly.

Attention must be paid.

 

Not running a fuel filter as per the original set up when I bought the Jeep (although seems like the consensus is its a good idea). Regarding the fuel pump, I can't say what specs it has. It's physically identical to the previously installed pump which looks like it was a Carter M2846. Since this design is basically a mechanical diaphragm pump, the fuel flow and pressure should be dependant of the engine speed and physical dimensions of the fuel side chamber, again looks to be identical so I'm assuming the same as before. Once I get a pressure gauge on it I'll know more.

Regarding the float settings and other carb vaugeries, the NOS rebuild kit I used had a set of detailed instructions and settings for various applications. Now whether I'm following them correctly is a different story as this is my first time delving into carb repairs. For right now I'm focusing on what was changed last.

I haven't looked in the service manual yet but any idea what pressure range the pump should be putting out?

 

Either too much pressure from the new pump, or some debris in the needle & seat.

 

Why not?




Your FSM is the most useful tool you have.

 

Fuel pump output and pressure has nothing to do with engine speed. It is controlled by steady spring pressure against the diaphragm. The action of the engine cam simply keeps the spring loaded as needed.

 

Is there a spacer between the pump and engine?

 

I had the same thought as JW. There was a spacer used on some of the dual action pumps, and not on others.

The spacer moves the pump out from the engine which changes the position of the actuator arm which also changes pressure produced.

 

x2,I just had to put a fuel pressure regulator on one, they like about 2psi,and have had a piece of debris get in the needle valve cause problems

 

Thanks for the comments. There was not a spacer on the old pump and because the the actuating arms looked to be of equal length I installed it back the same with just a gasket. I did check the inside of the fuel tank (also to replace brass float) for debris and it was surprisingly clean but probably worth it to take the top off the carb again and blow everything out with air. Thanks for the clarification on the fuel pump operation, I agree speed should not affect pump output pressure but certainly it has to affect fuel volume as the engine will consume more gas at higher speed (or do I have a conceptual error?).

 

In a sense. The volume delivered should be measured after detaching the fuel line at the carb. As per the FSM.

Pressure and volume are two different animals, and BOTH must meet factory spec. Imagine for instance a powerful pump but a tiny orifice. Pressure will read fine, but actual delivery volume will be near zero.

 

Was able to look at fuel system specs in FSM last night, clear data on fuel pressure and carb settings, nothing on volumetric delivery. I have been looking for a set up to measure the inline pressure but most modern kits today are designed for fuel injection systems which have much higher delivery pressures. I think putting an inline 0 - 10psi gauge just before the carburetor would be easiest but what has everyone else done? Thanks.

 

Thats what I did, set to #2,problem solved for me....I ordered a Holley on line

 

Read the chapter.

 

My vacuum guage will read fuel pressure.
Volume is in there should be a quart in 60sec

 

Thanks for posting. I'm guessing there's enough fuel in the bowl for the engine to run for one min.