There are a number of differences from the RX-0 to the RAKX-0 design. Among these differences:
A. Improved float and fuel valve
B. An economiser (in the RAKX-0)
C. Improvement in the size and spacing of the accelerator jets (in the main discharge nozzle).
Cast iron used on the RAKX-0 seems to be inferior to all other Carter brass bowl units. I do not know why. Often, the main housing in the area of the idle tube will deteriorate to the point of requiring metal-spray of the whole area and re-machining of the idle tube lower seat.
Idle issues with these carburetors are two-fold:
First (no offense meant) - the idle adjustment meters air, not fuel; thus in to RICHEN, out to LEAN the mixture.
Second - the idle tube on these carburetors forms its own upper seal when the tube is inserted into the carburetor. Removal of the tube and reuse will guarantee idle issues unless the tube is reformed. Carter printed often that the low speed jet should never be reused. This was good advice for the “parts replacer”; however the jet MAY be reused with some reworking. The reason that Carter suggested not to reuse the low speed jet is that the upper end of the low speed jet tube is inserted into a tapered passage. As the jet is tightened, the taper of the passage forms the upper seal for the jet. If one simply reuses the jet, the seal may not be perfect, resulting in a poor idle condition. However, one may CAREFULLY enlarge the upper diameter of the used tube by inserting a tapered object into the upper end (an icepick works). Thus the tapered passage will form a seal with the enlarged diameter.
As with the W-1 Carters, the "C" preceding the rest of the casting number simply means that this particular sample was built by Chevrolet in the Bay City plant under license from Carter.
Here is a link explaining which carburetor was original to which early Chevrolet:
http://www.thecarburetorshop.com/Kchevrolet1.htmNote the identification numbers used in the link. While service versions of the 150s (RJH-08) were the familiar Carter triangular brass; earlier carbs were tagged with a red cardboard tag. Good luck on finding any of these intact.
Opinion - while I offer these carbs for sale, and offer repair kits and parts for the carbs; I would highly suggest these units be used ONLY on number-matching show vehicles or museum vehicles. The carbs were not really very good and are quite expensive, parts (other than a clean-out kit) are extremely expensive, and some special tools are absolutely necessary when working on the units. I would suggest more modern replacement units for those who enjoy driving the vehicles. The later 6-cylinder RJH-08 150s are somewhat better; but even with these, more enjoyment would be possible with a replacement carb.
If I owned one of these cars, it would definately be the Canadian version ☺, and thus have the Detroit carburetor, which is light years ahead of the Carters of this period.
Jon.
