Motorcraft 4 Barrel Carb

AlexK wrote: Is this the corrosion / pitting Trader is talking about..? I have this kind of material break out on my carb just here.. I´m looking for a good throttle base for my 4300 or a whole carb, if someone wants to sell one, please let me know.

Ram Air Rick wrote: AlexK wrote: Is this the corrosion / pitting Trader is talking about..? I have this kind of material break out on my carb just here.. I´m looking for a good throttle base for my 4300 or a whole carb, if someone wants to sell one, please let me know.  Hello Alex,  My guess is that's a 1973 (D3FF) or 1974 (D4FF) AMC version Motorcraft carburetor. Can you look on the driver side (left side as you face the vehicle at the front) of the carb base and tell us what it says? Also... What vehicle is this on? year / model / engine / transmission ?  Thank you...  Rich

I just looked at receipts. I had bought 3 kits. $48 each. I was taking out the accelerator pump rubber within the second start up. That and I had fuel dribbling in the venturi nozzles at idle. After the 6th time taking it apart, i found that the bores for the accel pump were pitted badly and would take the rubber seal out. Pretty sure the fuel problem at idle was from that dumb dual setting at the needle valve. Like I stated earlier, I had the carb off the car maybe a dozen times. The last time, I split the rubber gas line at the carb...on the bottom. Didn't catch it. Started the car and a few seconds, it quit. Tried again and....backfire boom I had a fire. In my garage attached to my house. I had a fire extinquisher...it wouldn't put out a cigarette. Pushed it outside while still in flames.....get a water hose and get it out.....look and still see a puddle of gas burning on the garage floor.....a month later after my heart was back in my chest, I see from Holley, returned carbs. Wet tested and reboxed for $207 shipped. I pulled the trigger. Got it. Put it on and haven't touched it since. Set the idle speed once. The Autolites are in a box and I will maybe never look at them again.....

AlexK wrote: I have a wideband Air/Fuel sensor gauge, so I see what it is doing. I can even see how good the two stages of the Power Valve are working, lambda is going down then to around 0.85. It´s a little bit lean at cruising speeds (lambda @1.05-1.15).

Lean at cruise is normal. Best fuel economy and emissions was achieved on 1973-1980 engines with EGR and oxidation catalysts by running slightly lean at cruise. They didn't start running things dead on lambda until three way converters came out in 1981 since three way converters are only effective at lambda.