Petrol Strimmer Troubleshooting

This article covers the starting procedure for a petrol strimmer.

TABLE OF CONTENTS

• Cold Start
• Warm Start

First of all, make sure that you have used the correct fuel mixture for your machine. You will need to mix fresh unleaded petrol (not older than 4-6 weeks) with 2-stroke engine oil, at a 40:1 ratio. Please use the mixing bottle provided.

The engine requires different starting procedures depending on if the machine is in a cold or warm state. 'Cold' means starting up for the first time after you have not been using the machine for a good amount of time. 'Warm' means starting up again after switching off the machine and/or having left it off for a short while.

Cold Start

1. Lay the machine on a flat surface free of growth. Rest it on the motor and the protective housing.
2. Set Start/Stop switch to START position.
3. Press the primer bulb approximately 7 times (often enough so that no more bubbles are visible) - this injects the first amount of petrol that is needed to ignite the engine, 'priming' the carburettor.
4. Set the choke lever fully downwards to the 'full choke' position (indicator: horizontal line) - this closes the airflow, allowing a concentrated amount of fuel to go through.
5. Use your left hand to hold the appliance firmly by the rear handle.
6. Pull on the starter cord so that you feel resistance, then pull vigorously 3 to 4 times. 
7. When the engine ticks over it means that the engine has ignited.
8. Whilst it is ticking, set the choke lever to the half choke position (indicator: diagonal line) - this allows some air to enter the carburettor.
9. Pull the starter grip again quickly and strongly until the motor runs fully.
10. Please wait 30 seconds to warm up the machine before operating the product (ie. before pressing the throttle). Pressing the throttle will automatically shift the choke to 'Run' position.

Warm Start

1. Set the Start/Stop switch to START position.
2. Set the choke to the RUN position (vertical line) - this allows the highest degree of air-flow.
3. Pull the starter cord until the motor runs fully.

This article will cover the soft fixes that you can perform if your engine is not running properly.

TABLE OF CONTENTS

• Removing the Spark Plug
• Checking the Condition of Spark Plug
• Testing Spark Plug for a Spark - NOTE: Two People will Make this Check Easier
• Testing a different spark plug
• Reinserting the spark plug

Tools needed: Spark plug spanner tool (usually provided with the machine)

Removing the Spark Plug

1. Take off the spark plug cap (the thick black rubber cable which goes over the plug, also called the high tension lead).
2. Unscrew the spark-plug anti-clockwise using the spark plug spanner tool. This may require some force.

Checking the Condition of Spark Plug

• Please ensure that the spark plug is not dirty. When it gets covered in carbon, it can prevent the plug from sparking properly. If dirty, clean the end of the spark plug, preferably with a wire brush or with a cloth dabbed in petrol.

Testing Spark Plug for a Spark - NOTE: Two People will Make this Check Easier

1. Remove the spark plug, as described above.
2. Make sure the plug is clean, as described above.
3. Plug the spark plug back into cap, so that the end is dangling off.
4. Lean the tip of your spark plug against a metal part of your machine to earth it.
5. Make sure your Start/Stop switch is switched onto START.
6. Make sure you are in a shaded area so that you can observe it sparking.
7. Pull your starter chord strongly and observe the tip of your spark plug.
8. You should see a faint white flash - this indicates that the spark plug is working.
9. If you see no flash, then it could mean that your spark plug is not working.

Testing a different spark plug

1. If you have another petrol machine which is working correctly, you can take its spark plug off and test it on your machine as described above.
2. If this other spark plug is sparking, then this means that your current spark plug is at fault.
3. If it doesn't spark, then this means that your electrics are faulty - you will most likely need to replace the ignition coil.

Reinserting the spark plug

1. Once the spark plug has been cleaned and/or tested you may refit the spark plug into the engine.
2. Screw the plug in by hand to prevent cross threading, then use the tool to tighten.
3. Refit the cover, ensuring it clicks into place.

If the engine is running fast (revving high):

1. Please check the throttle cable, making sure there are no kinks found in it.
2. Also, make sure that the choke is disengaged and the throttle hold has been reset by pressing the trigger.

This article will cover the soft fixes that can be performed if you engine will not idle.

TABLE OF CONTENTS

• Carburettor Adjustment - L Screw Focus
• Unable to do this Procedure?:

If the engine is not running at idle speed and cuts out when you release the throttle trigger, then you need to do the following checks:

1. Fuel: Make sure it is fresh and correctly mixed (see 'Starting Issues').
2. Air filter: Make sure it is clean and unclogged.
3. Fuel cap: Make sure it's hand-tight (not too tight or too loose).
4. Carburettor: see below.

Carburettor Adjustment - L Screw Focus

It is quite likely that your carburettor settings need adjustment in order for machine to engage in idle speed properly again. This is a procedure which requires a high-level of mechanical skill, so please be wary before trying it. Doing this wrong could make the problem a lot worse. Please contact our helpline if you think you are unable to proceed:

Tools needed: Carburettor adjustment 'pacman' tool

1. Get the machine running and warmed up.
2. There are 2 adjustment screws on the carburettor, L which refers to low speed, and H which refers to high speed.
3. Firstly turn the L screw until the engine ticks over comfortably without the strimmer engaging.
4. To adjust the H screw the machine needs to be run on full throttle whilst adjusting the screw. 
5. The screw should be turned anticlockwise until the machine struggles to rev to max rpm (revolutions per minute), then turned slowly clockwise until the engine picks back up to max RPM.
6. This should then be set to go.

Unable to do this Procedure?:

If you are unable to do this procedure, then you could order a replacement carburettor, or better still, if you are still under warranty, arrange for your machine to be collected and repaired by our workshop technicians.

This article will cover the soft fixes for your petrol strimmer if the engine is not revving up.

TABLE OF CONTENTS

• Carburettor Adjustment - H Screw Focus
• Unable to do this Procedure?

If the engine is not revving up and cuts out before you reach higher revs then you need to do the following checks:

1. Fuel: Make sure it is fresh and correctly mixed (see 'Starting Issues').
2. Air filter: Make sure it is clean and unclogged.
3. Fuel cap: Make sure it's hand-tight.
4. Carburettor: see below.

Carburettor Adjustment - H Screw Focus

It is quite likely that your carburettor settings need adjustment in order for the revs to engage properly again. This is a procedure which requires a high-level of mechanical skill, so please be wary before trying it. Please contact our helpline if you are unable to proceed:

Tools needed: Carburettor adjustment 'pacman' tool

1. Get the machine running and warmed up.
2. There are 2 adjustment screws on the carburettor, L which refers to low speed, and H which refers to high speed.
3. Firstly turn the L screw until the engine ticks over comfortably without the strimmer engaging.
4. To adjust the H screw the machine needs to be run on full throttle whilst adjusting the screw. 
5. The screw should be turned anticlockwise until the machine struggles to rev to max rpm (revolutions per minute), then turned slowly clockwise until the engine picks back up to max RPM.
6. This should then be set to go.

Unable to do this Procedure?:

If you are unable to do this procedure, then you could order a replacement carburettor, or better still, if you are still under warranty, arrange for your machine to be collected and repaired by our workshop technicians.

Trimmer head / blade not moving:

1. Please check that either the blade or strimmer head is correctly installed - see: 'Changing strimmer head to brush cutter blade'
2. Please check that the shaft is correctly connected.
3. The best way to check if the shaft and head are correctly connected is to diagnose whether the drive cable is in a good condition, or if it has bent/twisted.
4. To do this: 1.) dismantle the two halves of the tube 2.) rotate the bottom head and look down the shaft whilst you're doing it - it should rotate smoothly. If not, then you will need to replace the lower shaft. 3.) if it is rotating smoothly, then it is likely the upper shaft which has failed. To double check this, you can turn the engine on and look down the upper shaft whilst you gently press the trigger, to check the same thing.  

1. Locate where the vibration is coming from: 
2. If it is from the engine housing, then ensure that all screws are fully screwed in place. If the vibration still persists, then the engine needs assessment by a mechanic/technician as it could be an internal malfunction.
3. If it is from the shaft, then it is likely that your inner cable has become twisted or bent and needs replacing. Take apart the two halves of the shaft and look down them whilst turning the strimmer head (lower), and running the engine (upper). This will tell you which half needs replacing. To order a replacement please Call our helpline, or purchase part on our website.

This article will cover the soft fixes if the pull cord is not working or faulty.

If your pull cord is not pulling out properly, is stuck, or is loose, then you would need to replace the whole 'starter assembly'. However, the fitting of this part on this petrol strimmer is very complicated due to the clutch cable which needs sensitive treatment. The instructions are below, but you need specialist tools and some mechanical dexterity.

If you feel unable to proceed with this, please contact our warranty & technical help team in order to discuss possible collection and repair of your machine. Alternatively, you can get a mechanic / technician to repair it. The 'starter assembly' part is available on our website or through our spares  helpline.

Note: If it is just the plastic handle which is damaged, and the cord hasn't retracted inside the machine, then you might just need to replace the 'starter grip'. Again, this is available either on our website or through our spares helpline.

Replacing Starter Assembly

WARNING: This procedure is complex, requires specialist tools and can be dangerous due to the clutch.

Tools required:

• Torx bit (T27/T25)
• Piston stop
• Precision pliers
• Clutch removal tool

Part required:

• Starter Assembly

1. Using torx (T27/T25) bit unscrew 4x screws on the cone connecting to the starter assembly.
2. Gently pull the cone from the starter assembly. 
3. Remove spark plug and replace with piston stop.
4. Using torx (T27/T25) bit unscrew the retention bolt down the middle of the clutch housing, then remove .
5. Remove retention circlip from top of the clutch. 
6. Using clutch removal tool turn clutch anti-clockwise and remove clutch and plate behind.
7. Using torx (T27/T25) bit unscrew the 4x screws on the starter assembly and 2x on the back side of the engine (Black plastic cover- ensuring the clip on the RH side joining the two covers is unclipped).
8. The starter assembly can now be removed and replaced.
9. Follow instructions in reverse to re-assemble (Ensuring clutch is tightened correctly and retention circlip is fitted. Also ensure when connecting the upper bar into the clutch housing ensure the main drive bar is fitted correctly- ie fits into slot, not around. If the bar is not fitted correctly there will not be any drive to the shaft).

This article covers changing from grass trimmer to brush cutter and from brush cutter to grass trimmer.

TABLE OF CONTENTS

• For the GDB30B, do the following
• Changing from Grass Trimmer to Brush Cutter
• For the RG415, do the following

There are two types of Qualcast petrol brush-cutters: 1. GDB30B, 2. RG415 - 495409

For the GDB30B, do the following:

Changing from Grass Trimmer to Brush Cutter

1. Align the slot (C) in the flanged washer (D) with the slot (B) in the gear head (A).
2. Place the hex wrench (K) through the slots in the flanged washer (D) and gear head (A) to lock them together.
3. Unscrew the grass trimmer head assembly (F) by hand in clockwise direction.
4. Remove the cupped washer (E) and flanged washer (D) and then retain it for the blade installation. 
5. Place the flanged washer (D) over the gear head shaft (G) with the hollow side toward the gear head (A). 
6. Center the blade (H) on the flanged washer (D), making sure the blade fits flat and the raised hub of the flanged washer goes through the hole in the blade.
7. Install the cupped washer (E) with the raised centre away from the blade.
8. Place the blade nut (I) onto the gear head shaft  (G).
9. Place the hex wrench (K) through the slots in the flanged washer (D) and gear head (A) to lock the heads rotation while tightening the nut. 
10. Install the blade nut (I) by turning it counterclockwise (left handed threads). 
11. Tighten the blade nut (I) securely by wrench (J).

• To change from the brush cutter to the grass trimmer, please follow the instructions in reverse order.

For the RG415, do the following:

1. Hold the flange with an allen key. 
2. Unscrew the nut at the bottom clockwise, which will allow you to take off the blade.
3. Remove another shield-layer.
4. Still holding onto the flange, fit the strimmer-cutting head onto the shaft.
5. Rotate anti-clockwise until it screws fully in place.
6. Remove allen key.
7. To put the blade back on, remove the strimmer-cutting head and place the shield-washers, the same way you took them off.

Anti-clockwise to tighten the bottom nut^. Make sure to keep the upper flange in place with the allen-key whilst doing this.

This article will cover the procedure of fitting the strimmer line on your petrol strimmer.

TABLE OF CONTENTS

• For the CDB/GDB
• For the RG415-495409 & BC260/QGTP25

For the CDB/GDB:

1. Twist off the spool cover/bolt-cap (for GDB30B: clockwise to loosen; for CDB: anti-clockwise to loosen) and then remove it. Do not lose the spring!
2. Remove the spool and remove the remaining line.
3. Make a nick in the middle of the new line, and hook it into the slot in the middle of the spool.
4. Wind on a spool line on each side of the spool in the direction shown by the arrows.
5. Press both lines into the opposite slots and thread the lines into the openings of the spool casing (the eyelets).
6. Carefully push the line spool with its spring into the spool casing.
7. When doing so, pull the lines out through the eyelets.
8. Press the line spool in, and turn it clockwise as far as the stop.
9. Keep hold of the line spool and twist it slightly back. The line spool must remain firmly fixed in the pushed in position.
10. Screw the cover/bolt-cap back (GDB30B anti-clockwise ; CDB clockwise ) onto the line spool and turn it by hand. Adjusting the lines to the right length.
11. Push on the underside of the line spool by hand and pull out both lines until they are somewhat longer than the edge of the protective bonnet.

For the RG415-495409 & BC260/QGTP25:

This article covers the procedure of fitting the fuel lines on your petrol strimmer.

To replace them on your machine, follow these instructions (these are for the CDB models, but should apply to others too):

1. Firstly, feed the fuel line through the hole from the outside of the tank, feed it all the way through until there is a little bit left poking out the top like in this picture below:
2. You can then attach the fuel filter from the tank cap opening, the fuel pipe will stretch a little to get better access:
3. Then pull the fuel line back from the outside and attach it to the carburettor inlet:

           This video is for the CDB30 grass trimmer, however it still applies in principle to other 2-stroke engines.

1. Drain remaining fuel out of tank (you don't want it forming residues over winter, due to condensation).
2. Run the machine to use up all the fuel inside your carburettor.
3. Press priming bulb to inject remaining fuel. Try to start up. If it doesn't start up, then your preparation for winter is complete.

           Store in a dry place.