Question - What do all of the following items have in common?
(A) Carter YF Chevrolet replacement carb
(B) Stromberg BX series Chevrolet replacement carb
(C) Zenith 228 series Chevrolet replacement carb
(D) Carter W-1 1946-48 Chevrolet original carb
(E) 15 year old boy pouring gas into the engine out of a boot
Answer - They all provide more reliable carburetion than the Rochester B!
The Rochester B has a major problem, and several others which have been created by Dr. Goodpliers (Mr. Goodwrench's evil twin
). The major problem (as mentioned earlier in this post) is warped castings. Rochester used only 4 screws to hold the airhorn (top casting) to the bowl center casting). 8 should probably have been used. Clean the castings, then assemble the airhorn to the bowl WITHOUT a gasket, and hold so that the assembly is between you and a lighted light bulb. If you see light, the castings are warped.
The correct way to solve this problem is with an oven and some simple jigs which are easy to make. Using a feeler gauge, measure the distance between the two castings. After placing the assembly in the jig, tighten the jig to remove 0.003 as measured by the feeler gauge. Heat the assembly in an oven at 400 degrees F. for 1 hour. Allow to completely cool. Repeat this process until the castings are true.
The induced problems occur because the commercial rebuilders interchange parts on these carbs with no regard to jetting or the pressed-in airbleeds (different for different years, car or truck, transmission type, etc.).
The fact that your carb does have a tag may mean Dr. Goodpliers has not yet seen your carb, and if you don't mind caring for the warpage, it may be useable after a rebuild.
If looking for a kit, take the number from the tag AND YOUR OLD ACCELERATOR PUMP with you to the parts house. The cheaper kits will not have a pump - avoid. The better kits will have a pump BUT IT WILL BE THE INCORRECT NEWER STYLE PUMP - avoid. Your pump is the old style where the top stem of the pump is flat metal with a retangular slot. The pump arm is inserted through the slot and held in place by a spring. The new style pump has a round stem with the pump arm sliding over the stem. They are not interchangable!!! Since the kits are packaged with a see-through cover, make sure the pump in the kit is like your pump.
The best kits will contain the correct pump, as well as the correct main jet, power piston spring, power valve, etc.
If you have difficulty acquiring a suitable kit locally, there are specialty companies which produce such kits. They are available.
With all due respect to the gentleman who posted about the sensitivity of the B to float settings; ASSUMING THAT ALL PARTS IN THE CARB ARE UP TO PAR, THE B IS NO MORE SENSITIVE THAN ANY OTHER TO FLOAT SETTINGS. Set it to specification, and it will work!
Other parts that should always be replaced when building a B are the power valve (plug, small spring, and ball) and the power piston spring (long spring under the power piston). The power piston spring is a tensioned spring, and fatigues. This is the control for the power valve (or economiser valve if you are a Holley fan). A fatigued spring will give unpredictable results.
If you address all of these issues, the B is a very simple carburetor, and rebuild should give a few years service before going through the entire procedure again!
Personally, I would go with the YF replacement or one of the others mentioned in the "question" (even the 15 year old)
Jon.
