Welcome to your guide to the Morris Minor fuel system! Whether you’re a proud new owner or just starting to tinker with your Minor, this page breaks down the key parts of the fuel system—simply and clearly.

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The Morris Minor used 3 types of SU Carburettors, depending on the model:

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• Series MM: H1 Carburettor

• Series 2: H1 Carburettor

• Morris 1000 to 1960: H2 Carburettor

• Morris 1000 from 1960 onwards and all 1098 models:HS2 Carburettor

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As the HS2 is the most commonly used Carburettor, this page refers to the HS2

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The Morris Minor uses a simple, mechanical fuel system. Here's the basic flow:

1. Fuel Tank – Stores petrol at the rear of the car.
2. Fuel Pump – Sends petrol forward to the engine.
3. Fuel Filter (if fitted) – Removes dirt or debris.
4. HS2 SU Carburettor – Mixes petrol with air to feed the engine.
5. Engine Combustion Chambers – Burn the mixture to power the car.

Good to know: The Morris Minor uses gravity and low pressure—no electronics or high-pressure systems like in modern cars.

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1. The Fuel   Tank

• Located in the rear boot area, under the floor.
• Filler cap is on the passenger side rear wing.
• This  is  Connected to the fuel line running to the front of the car.
 

2. The SU Fuel Pump

• The SU fuel pump is mounted on the bulkhead (engine bay firewall).

• It clicks when priming—this is normal!

• It pulls fuel from the tank and pushes it toward the carburettor.

• If you hear it ticking constantly, there may be an air leak or fuel blockage.

3. The  SU  HS2  Carburettor

What it does:
• Mixes petrol and air in the right ratio.
• Sends the mixture into the engine through the inlet manifold.

Key parts of the HS2:
• Dashpot – holds oil and dampens piston movement.
• Jet – where petrol enters.
• Needle – moves up/down to control petrol flow.
• Throttle Butterfly – opens when you press the pedal.
 

Maintenance  Tips  for  Your  Carburettor

• Check dashpot oil monthly – use SU carb oil or Penrite carb oil
• Clean the air filter – helps airflow stay smooth.
• Watch for leaks – especially around fuel lines and the carb body and float chamber.

Did you know? The HS2 carburettor is easy to tune and maintain—ideal for DIY mechanics.

​​​​​​Upgrade Suggestions

• Add an inline fuel filter – Helps keep dirt out of the carb.

• Get a Carb rebuild kit– Can restore performance.

• Electronic fuel pump (optional) – Modern alternative to SU pump.

• Install upgraded ethanol proof fuel hoses, using proper hose clips

 

 

​See  these  videos  to  understand  your   fuel  system  better:

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Final Tips

• Keep a fire extinguisher in the boot—older fuel systems can leak.

• Use modern unleaded petrol, E5 preferably

• Learn how to tune your HS2—it's a rite of passage for Morris Minor owners!

• Upgrade fuel hoses to ethanol proof hoses and use proper hose clips

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