During a long winter lay-up the petrol in your tank ages: volatile components evaporate, a sticky residue (gum) forms and the quality drops. On classic cars with a sensitive carburettor that often leads to hard starting, contamination and leaks in spring. Fresh fuel, a stabiliser and a clean carburettor spare you all that trouble.
The cold months are here again, and for many classic car owners that means the car is heading into winter storage. But what actually happens to the fuel in the tank during that long spell of standing still? Contamination, deposits and hard starting in spring can really take the shine off the driving season. In this article we explain exactly what happens and how you can stay ahead of it.
Why this matters
Classic cars often have a sensitive fuel system. Unlike modern vehicles, a carburettor copes poorly with fuel standing still for months. Petrol starts to age over time: volatile components evaporate, a sticky residue (gum) forms and the quality drops. That directly affects how the carburettor works and how the engine starts once spring comes around again.
Common problems after winter
When a classic car is started after winter storage, we tend to see the same symptoms:
- The engine starts poorly or refuses altogether.
- The idle is uneven.
- Fuel is leaking.
- The carburettor is dirty or blocked with deposits.
- Gaskets and seals have dried out or hardened.
These problems build up through long standing and aged fuel, rather than appearing overnight.
Our approach at Carburateur Service Nederland
At Carburateur Service Nederland · your carburettor specialists in the Netherlands · we know exactly what standing still does to a carburettor. Our way of working focuses on prevention and repair:
- Inspection · we check the carburettors thoroughly for wear and contamination.
- Ultrasonic cleaning · every passage and jet is deep-cleaned, so old deposits disappear.
- Setting up · after cleaning we set the carburettor up exactly to factory specifications.
- Testing · we check on the engine that the carburettor is doing its job cleanly and smoothly.
Our workshop and shop are at Huizerweg 49, 1401 GH Bussum, the Netherlands, where craftsmanship and a love of engineering come together.
An example from the workshop
A customer recently brought us his classic for a winter service. The carburettor turned out to be full of deposits, which made starting nearly impossible. After a thorough ultrasonic clean and set-up the car ran like new again. Our advice to every classic enthusiast: check the fuel before winter storage and consider a stabiliser to keep deposits at bay.
Tips for maintenance and prevention
- Fill the tank with fresh petrol before winter to keep condensation at bay.
- Always use 98 octane super unleaded instead of E10; it protects rubbers and gaskets.
- Add a fuel stabiliser to preserve the quality of the fuel.
- Run the engine briefly once a month, so everything keeps moving.
- Check gaskets and fuel lines for drying out.
Conclusion
Winter storage goes smoothly as long as you prepare properly. Good fuel, a clean carburettor and a timely check make the difference between starting first time and endless spannering in spring.
Have your carburettor checked or overhauled at Carburateur Service Nederland in good time, and you will begin spring with a clean start.