Mar 2, 2012 update to the Mercedes-Benz 230 S project car

Carburetor Rebuild

The Mercedes 230 S came with twin Zenith two-choke, downdraught carburetors. Ours needed rebuilding badly.
The Zenith wasn't the simplest carb we've ever worked on, but it was straightforward. A good cleaning and rebuild solved our startup issues.

Obviously we had a fuel issue in the idle circuit.

Next up, we had to deal with our Benz’s carburetors. Our 1966 Mercedes-Benz 230 S was loath to start unless we squirted a bit of carb cleaner or starting fluid into the air inlet. Obviously we had a fuel issue in the idle circuit, and since the problem persisted regardless of whether engine was hot or cold, we ruled out the choke as the problem.

The 1966 model came with twin Zenith carburetors, while its 230 SE sibling sported a mechanical fuel injection system. Although early Mercedes fuel injection works surprisingly well, we were pleased that our car was equipped with the more conventional Zenith carb setup. They have a good reputation, and our buddy Rennie Bryant at Redline BMW found us carb kits for about $20 per. This would prove way cheaper than messing with early fuel injection.

We decided to rebuild the carbs one at time. That way, if we lost our way somewhere in the process, we’d have a completely assembled carb for reference rather than a bench covered in tiny pieces. On teardown we immediately discovered worn out accelerator pumps and one bad choke. A trip to a local junkyard netted us another choke spring for $5, and the rebuild kits had replacement accelerator pumps. By the time we had the first carb rebuilt, the car ran fine again. We will rebuild the second carb just as a matter of insurance.

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