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How do you change the engine speed of a Mechanical Perkins 1103, 1104 and 1106 Generator Engine?

Does my 1103, 1104 or 1106 Perkins Engine have an Electronic or Mechanical Governor, or an ECU?

This article only covers the mechanical 1103, 1104 and 1106 engines in the Perkins 1100 series. If your engine has a Mechanical governor you can change the speed using simple tools. If you have an engine with an electronic governor, you will need the Perkins LC Governor software to change the speed. If your engine has an ECU, you will need a Perkins Dealer or OEM with the Perkins EST software.

To find if your engine has a mechanical or electronic governor, you need to find the fuel injection pump. On the Perkins 1100 series, the mechanical engines have a throttle screw mounted on the top of the pump. For electronic governor controlled engines, they have an LC governor mounted on top of the pump.

For ECU controlled engines, you will see an ECU mounted on the side of the engine.

How do I change the speed on my Perkins 1100 series with a mechanical governor?

Before considering a speed change, consider the following points carefully. If you aren't sure then you should seek a professional to assist you, such as a Perkins dealer.

  • Changing the speed on your generator will result in the electrical output frequency changing. 
  • You can make fine speed adjustment (a small adjustment), or a ratings adjustment (from 1500RPM 50Hz to 1800RPM 60Hz).
  • When you change a mechanical engine, there is no guarantee you will get the rating on the ratings chart / specification sheet. If you need to guarantee the power, you should order the correct rating or electronically switchable rating from your local Perkins dealer.
  • You should always be sure if you are switching ratings that the rating you require is actually available, not all engines are available to run at all ratings. Check with your local dealer.
  • If you have an alternator, you may need to adjust the UFRO and overspeed protection on the AVR. Consult with the manufacturer of your unit prior to changing the speed.

After checking the above points, you can proceed to change the speed as follows:


This picture shows the throttle screw on top of the fuel pump.

Run the engine off load.

To adjust the speed first loosen the nuts (3 and 4). If this is not done then damage may occur.

Once loose then adjust the screw (5) clockwise to increase the speed, or anti-clockwise to decrease the speed. For running at 50Hz, set the speed to 52.5Hz, for 60Hz about 63 Hz. When full load is applied to the set it will run at 60Hz, because of governor droop.

Retighten the two nuts. 

The engine is then set to the speed required. You can now stop the engine.

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