Chris - you asked about the carburetor (US spelling
) so all of your answers have been about the carburetor. And yes, it is quite easy to "throw rocks" at the Rochester B.
However:
A perfect (generally not a term one would use with the Rochester B
) carburetor coupled with a defective ignition system or poor compression will cause a very rich condition.
So, a suggestion:
Prior to rebuilding the carburetor, first make sure you do not have an electric fuel pump, then do both a compression test, and a comprehensive ignition test.
ONE TEST IS WORTH 1000 OPINIONS!
If both the compression test is normal, and the ignition is good, then look at the carb.
When new, the Rochester B tended to be slightly lean, with a slight bog or hesitation often occuring. As ethanol has less energy content, this condition is worsened by the use of ethanol fuel.
Over time, the Rochester B goes from slightly lean to very rich. This, as mentioned above, may be caused by a stuck power valve. But it may also be caused by warped castings. And, as mentioned above, the incorrect mounting gasket will cause the power valve to always be open from the moment the carburetor is installed.
Ethanol DOES do long term damage, but we are talking about decades, not months or years. Over a couple of decades, the ethanol can cause holes to form in the bottom of the zinc alloy fuel bowl. Again, very long term, not short term. Short term damage would be to a neopreme accelerator pump. For some reason, neopreme after being in ethanol and then allowed to dry out, will turn hard. As an accelerator pump must flex to function, this issue can cause the accelerator pump to cease to function. This is generally not an issue with a vehicle that is driven daily, as the accelerator pump never dries out. The really good rebuilding kits have leather accelerator pumps that eliminate this issue.
You mentioned a possible switch to a Carter. The replacement Carter's are a type YF which has a diaphragm style accelerator pump (also neopreme), so is subject to the same issue. Vehicles that are driven daily tend to have a lot fewer issues. Carter YF's in both hot air choke and manual choke are available for the 216. Since the YF uses a diaphragm, leather is not possible.
Another possibility which solves the ethanol issue is the older Carter W-1 used on Chevrolet up through 1949. The bowl is cast iron, so no porosity issues; the pump is leather, so no pump failure issues. Should you opt to go this route, look for either a Carter W-1 483s or Carter W-1 574s.
The Rochester B gets a lot of bad press (mostly well-deserved), but make sure that it is the problem. Even a Carter W-1 with a defective ignition or poor compression will run rich!
Jon.
