Automatic choke on a 2.5 MK4 engine

I have now it is a bit colder seriuos problems starting the engine. My feeling is that the automatic choke is enriching the mixture to much. (though I am not sure). Anybody has some tricks to get the engine running?

If it’s stone cold then being too rich is seldom a problem.

Try giving it some “easistart” without the starting carb connected and once it’s warmed up you can set up the starting carb if needed.


Thanks Peter,
How do I disconnect the starting carb?

Hi Ron,

On the top of the solenoid are two connectors just disconnect the one that connects via short wire to the thermostat on the water manifold.


Thanks Guys,
Disconecting the choke (electrically) solved the problem!

Hope it starts when its cold.

With a little help yes it does (7 Celsius in the garage)

| Allrand Randall Botha
January 12 |

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Hope it starts when its cold.

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The starting carb, including its electrical system, has made engine fires over the years. I’ve seen burned engine bonnets. The electrical system wiring in its normal state has a live electrical wire in the middle of the carbs for this operation. A spark is fraught with danger there. Additionally, sometimes there is blowback through the starting carb line from the engine, providing wonderful air/fuel mixture right there. And some cars have a gasoline leak collection pan under the carbs to have additional fuel near the potential spark source. There are fixes available for all these terrible scenarios. Just be very careful your wires are sufficiently protected from potential sparking.

On my car, I have the starting carb wired to a pull switch under the dash. The wiring only has voltage in the carb region when that pull switch is pulled. After about one minute running the cold engine, I push the pull switch to off so no wire in the starting carb circuit has any voltage.

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The ASC is safe and it works well if properly adjusted including the switch and main mixture.
Robs picture shows what to do. The test is to ground the wire at the otter switch when the engine is hot and running and observe if it runs over rich/ adjust it past highest rpm to a certain lower rpm. Then it works.