Carb numbers,

Looked at the three 269's I have. The two later 40's have the correct number BBR that Carbking's list shows it should have, the '42 has a Zenith that comes back to a FAC 241! All could do with a overhaul, but not sure if I should stick with the "incorrect" Zenith. I wonder how it got there. Not much different between a FAC and BLD 269. I might just "run what I brought".

Just picked up the IHC shoptalks that cover the Zenith and Carter Carbs. Should have some good info.

I picked up a "core" Zenith 228 that was an IHC number correct "replacement" carb with adjustable main metering jet. Lots of white powder inside and the accelerator pump was seized in the bore. The Zenith I took off my '42 has the accelerator pump check valve that is seized in the main body and will not come out with a slide hammer (factory method for removing).
I wanted to have another carb to experiment on before I tackled the original.
I drilled in the bottom of the passage that the check valve and accelerator pump is in. I then took a small punch and drove the check and seized accelerator pump out. To re seal the hole I used a lead sinker from my hardware store. Today the replacement check valves came and I re assembled the "core" carb. I got it installed and started the adjustment process. Truck runs great and the idle mixture and speed is set. I'll have to pull the plugs a "read" them to see if I have got the main metering correct.
Next up is to drill the original carburetor and drive out the bad check, then build back up.
Then I have 2 Carter BBR's to overhaul and 2 AC fuel pumps to do.

A coupla of 14 mile runs at speed, while adjusting the main mixture. Pulling and reading the plugs at the end of the run, I think I now have it "dialed in".
Truck runs better than it has in years, part of it was a fuel pump issue, it would pump fine for a while and then it would draw air (seen from the sediment bowl) and when it would pump pressure and volume were fine.
Carb just had deteriorated over time, and since I don't drive it much, didn't address it until it got real bad.
I have to finish up the other Zenith and then go on to the Carter Ball & Balls. Also have 2 fuel pumps to overhaul.
Before I retired, I didn't have the time to play around with these trucks, now I am getting to things.

Got the original Zenith back together and ready to install.
I had a Ball & Ball (Carter) on my spare engine, put it briefly on the '42 and found it running very rich.
Needs throttle shaft bushing, Accelerator pump linkage and a good cleaning, but the real reason for running rich was a poorly repaired float. Old float weighed 17 grams new float weighs 13 grams.

Second Zenith done and on the 1948, starts and runs good. I should get a set of new spark plugs in the '48. I have no idea what it has in it, but the spare had resistor plugs as did the '42 which is not good with the old 6 volt ignition. The '42 had them because that was all I could get at the time, I have since special ordered, and replace them with non resistor plugs and they make a difference in the '42 and I expect the same on the '48.
The 1st Ball & Ball needs a float and throttle shaft bushings, the one the came off the '48 the throttle shaft feels good, so likely needs a good cleaning and new gaskets.