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GPS520 Assembly Instructions

Before starting assembly:

  • Please do not remove the trimmer blade sheath before attaching it to the trimmer head. The sharp blade tips present a high risk of injury.
  • This is a sizeable piece of kit, so the assembly process should ideally be carried out in a place with plenty of open space to allow manoeuvring of the tool without risk of accidents.
  • Ensure all the components below are included in the box. Should any of those parts be missing, contact SGS customer service straight away.

Included with your trimmer:

Tool kit


Mixing jug

Working shaft

Spool & blade


Main shaft


Step 1: Installing the Handle

Remove the top holding piece (A) by unscrewing the 4 screws. The handle has to be placed offset, with the throttle assembly slot sitting closer to the main shaft, as shown below.

Place the holding piece back on and screw in the 4 screws. Ensure the handle does not rotate backwards or forwards. Once the handle is sitting in the correct position, tighten the screws firmly using the larger of the two hex keys provided.

Step 2: Installing the throttle assembly

Remove the screw & nut that go through the base of the throttle assembly and slot it onto the handle. If you meet resistance, rotate slightly left and right while pushing down.

Once the hole at the base is aligned with the one on the handle, re-place the screw & nut to secure the throttle assembly in place and tighten with the screwdriver provided.

Step 3: Installing the cutting attachment guard

Unscrew the four fixing nuts

Place the guard as shown below and tighten the screws/nuts, in the setting appropriate for the trimmer head you intend to use.

There are two trimmer guard settings, depending on the trimmer head in use.
The guard sits closer to the head when using the blade and further away when using the line trimmer head.

Step 4: Installing the cutting attachments

a. The blade attachment: Insert the smaller hex key into the hole on the side of the gear case ensuring that it also goes in the hole in the axle plate to prevent the axle from turning.

Remove the axle nut by turning clockwise.

Once the axle nut is off, you can remove the two washers.

Place the blade on the axle, followed by the axle washer, then the mount washer.

Finally, place the axle nut back on and tighten it by turning counter-clockwise, while again locking the axle with the hex key. It is ideal to remove the blade sheath at this stage, before starting the machine.

b. The line trimmer head: The spool screws straight onto the axle. Remove the two washers as shown in the section above and attach the spool by turning counter-clockwise.

Step 4: Connecting the working shaft to the main shaft

Remove the rubber caps from the ends of both shafts.

Loosen the locking knob if necessary. Press and hold the "Push" button to allow the working shaft to be inserted into the tube coupler, while gently rotating during insertion to ensure the drive shafts align properly. Release the "Push" button to lock both shafts in position. Finally, tighten the locking knob by turning clockwise.

Step 5: Putting on the harness and balancing the strimmer

Put the harness on and adjust it for a snug fit. Ensure the hip guard sits on the side of your hip/thigh and not at the front. You can adjust its position by sliding it backwards or forwards on the supporting band.

Attach the strimmer and let it hang off the harness. Make further adjustments until you reach the desired working position.

Step 6: Mixing the oil and fuel

Note: Use only 2 Stroke Engine Oil to ensure proper engine functionality. Using the wrong type of oil can result in engine damage or even failure, along with voiding the warranty.

In the provided mixing jug, mix fuel and oil in a 40:1 ratio - 40 Fuel and 1 Oil. Always add fuel first up to the marking on the jug, then the oil up to the indicated level. Put the cap back on and shake a few times.

Step 7: Fuelling the strimmer

Note: Fuelling must always be done with the engine turned OFF, ideally with the strimmer laying on bare ground.
Remove the fuel cap and carefully pour fuel through the smaller nozzle. If the fuel tank is empty, the entire contents of the mixing jug can be poured in. This is also the maximum amount of fuel/oil mix that should be in the tank at any time.

Step 8: Starting the strimmer

Press the priming bulb 5 to 8 times. This will help the strimmer start with fewer pulls of the starter cord.
Set the strimmer switch on the throttle assembly to ON (I).

For a cold start, move the choke to the "Start" (closed) position and squeeze the throttle trigger once.

Hold the strimmer engine in place and pull the starter cord firmly all the way. The engine should start after 3 to 5 pulls. DO NOT let go of the starter cord handle when pulled out or you risk smashing it against the engine body. Also, allow the starter cord to go back all the way in before pulling again. Once the engine is running, set the choke to "Run" (Open) position.

Once the machine is running, squeeze the throttle trigger to rev the engine 2-3 times, then let it run idle for 30-40 seconds. After this, your strimmer should be ready to use.