How to Synchronize Dual Volkswagen Carburetors?

VW Carburetor: How to Rebuild Dual Carburetors?

The carburetor in VW cars shifts the right amount of gasoline or any other type of fuel into the cylinder. The parts within the carburetor, including vacuum lines that regulate the flow of fuel, could become damaged over time, which could harm the performance of the vehicle. In order to rebuild, you need to first give it a good clean and then move further to change the worn or damaged components. Follow this guide to know detailed steps for synchronizing dual Volkswagen Carburetors on an air cooled engine. When reconstructing your vehicle’s carburetor, clean it properly first and the go ahead and substitute the worn or damaged parts.

rebuild dual carburetors

Preventing the Vacuum Leaks

Before you start off with the process, take out the air cleaners, ensuring that there is no vacuum leak and apply fluid spray around the intake manifolds and carburetor base, while the engine is intact. The engine’s valve adjustments, and ignition timing need to be correct as well and you should be adjusting or synchronizing the carburetor of a tuned engine, not the one suffering from many problems.

2 Main Ways to Synchronize Carburetors

There are many ways in which you can synchronize two carburetors; here you can see 2 methods, having more or less same procedure, but using different tools. One tool is Snail gauge (also called as SK tool) and the other one is Uni-sync.

rebuild dual carburetors

The SK Tool

The SK tool has been in the industry since 15 years, while the Uni-sync from more than 5 decades. Uni-sync is the traditional form of the tool, while Snail gauge is more accurate and modern tool. The Uni-sync makes use of piston or ball in a plastic/glass tube. The ball moves higher in the plastic, if there is more airflow through the carburetor.

Make sure that there is no vacuum leak below the system and when placing the tool, it should be sealed tightly at the top of the carburetor throat with no gaps or air bypassing. SK or snail gauge is an airflow measuring tool that determines the flow of air into the curb accurately.

The SK Tool isn’t restrictive and hence can be used to measure airflow both externally and internally vented carburetors. The only requirement needed here is that carburetor or gauge connection shouldn’t allow any air leakage. Unlike uni-sync, this tool would be inserted into the top of the carburetor and you can make use of adapter for connection purpose that ensures no leak.

Before You Sync

When synchronizing, first warm up the engine’s operating temperature and then cut off the carburetor connection from one or both. Rotate the disc, before placing the tool on the top of one throat and no matter how air is flowing, you need to ensure that speed of the engine remains idle and if the speed changes, there is a chance for vacuum leaks.

If you want more air flow, then turn the screw in clockwise direction and vice-versa for less air. You will have to match the airflow intake from side of the engine as well.

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