Carburetor - douging

I was hoping not to touch the carburetor for quite a while but the engine cranks and doesn't start so we dug into it now. I know a little about carburetors but not enough and pulling one apart gave me a lot of insight. It still seems too complicated for what it actually does and this is supposed to be an extremely simple design!

Our Jeep has the same single barrel carb as any other original CJ2A - Carter W0 (or WO) model 636SA. It was used on multiple Willys models and a Studebaker. Rebuild kits are available from everywhere. I ordered one from Jeep1942.com because I liked the seller's personal touch and upfront product listing.

Luckily there is a spare CJ2A engine in my Uncle's shop (actually two). It's not worth much as it was under water at one point and the head is off. But it had a complete carb on it so I pulled it off and took it apart on the bench. That told us a lot. I used the rebuild kit on the spare while we continued working on the original carb. Rebuilding, cleaning, and re-assembling the spare carb gave me tremendous confidence in the mechanics of the carb but very little education on how it worked.

Photos

  • Carburetor

    Lots of gritty oil and surface corrosion. It’s not rusted shut or frozen but it’s not squirting fuel.

  • Carburetor

    I removed the cover on the carb bowl. Inside is an orange fluid: rusty gas! Those tiny rust particles will clog the jets and keep fuel from flowing. 2019

  • Carburetor

    Carb float, metering rod, and plunger. 2019

  • Carburetor

    Spare carb. I pulled this from an engine that sat at the bottom of a oil change pit for 40 years. All valves worked and none of the hardware is seized. I disassembled it to learn from. 2019

  • Carburetor

    Spare carb. I pulled this from an engine that sat at the bottom of a oil change pit for 40 years. All valves worked and none of the hardware is seized. I disassembled it to learn from. 2019

  • Carburetor

    Spare carb. I pulled this from an engine that sat at the bottom of a oil change pit for 40 years. All valves worked and none of the hardware is seized. I disassembled it to learn from. 2019

  • Carburetor

    Spare carb. I pulled this from an engine that sat at the bottom of a oil change pit for 40 years. All valves worked and none of the hardware is seized. I disassembled it to learn from. 2019

  • Carburetor

    Cleaned and treated with Zinc Phosphate. Ready for taping and priming.

  • Carburetor

    Fresh coats of paint before assembly!

  • Carburetor

    This is the idle port jet. I was matching up original parts to the rebuild kit and making sure none were left over. A little jet kept nagging at me because it wasn’t in my pile of original bits and I couldn’t locate it on the carb. I figured it was maybe an extra piece used on early models but not this one. But more studying of the assembly diagrams and I narrowed down which port it was. With a flashlight and pick I was able to see this little guy buried down in the carb. Lucky I found this as it was blocked and would have been a big headache later on.