Petrol brush cutter cg430

[Tony 1]

Afternoon all.

I have a cg430 brush cutter petrol strimmer and a couple of days ago it cut out as I think the fuel was low but now it will not start after refuelling. I've checked the air filter and took apart the carburettor just to have a look which all appears fine and I checked the spark plug which again appears fine. When I put it all back together it did start for only a couple of seconds then dies. Any ideas what else I can check. I've not got a manual for it but what is the setting for the single fuel adjuster screw? Thanks in advance.

 

[Swwils]

Fuel Line and Filter: Check the fuel line and filter for blockages or damage. A clogged fuel filter can prevent fuel from reaching the carburetor.

Spark Plug: Although you've already checked the spark plug, it might be worth re-checking. Make sure it's not only clean, but also properly gapped and is sparking correctly. You can use a spark plug tester for this, or if you don't have one, you could consider replacing the spark plug entirely as they're usually quite cheap.

Carburetor: It's possible that the carburetor may be partially blocked or have a minor fault that isn't immediately visible. You could consider giving it a deep clean using a carburetor cleaner, or if you're comfortable doing so, disassembling it and manually cleaning all the components.

Fuel Mixture: You might also want to double-check the fuel-oil mix you're using. Using the wrong mixture can lead to starting problems and poor performance.

Exhaust: Sometimes the exhaust port or muffler can get blocked with carbon deposits which can stop the machine from starting. It's worth having a look at these and cleaning if necessary.

Adjustment Screw: For the fuel adjustment screw, it can depend on the exact model of the engine, so it's difficult to provide exact instructions. As a general rule though, you could try gently turning it all the way in (clockwise), then turning it back out (counter-clockwise) about 1 1/2 to 2 turns as a starting point. From there, you can fine-tune it based on the engine's performance. Turn the screw in small increments, waiting a moment for the engine to respond. The aim is to find the point where the engine runs smoothly, without any stalling or excessive smoking. Be careful not to over tighten the screw as this can damage the seat.

 

[Tony 1]

Fuel Line and Filter: Check the fuel line and filter for blockages or damage. A clogged fuel filter can prevent fuel from reaching the carburetor.

Spark Plug: Although you've already checked the spark plug, it might be worth re-checking. Make sure it's not only clean, but also properly gapped and is sparking correctly. You can use a spark plug tester for this, or if you don't have one, you could consider replacing the spark plug entirely as they're usually quite cheap.

Carburetor: It's possible that the carburetor may be partially blocked or have a minor fault that isn't immediately visible. You could consider giving it a deep clean using a carburetor cleaner, or if you're comfortable doing so, disassembling it and manually cleaning all the components.

Fuel Mixture: You might also want to double-check the fuel-oil mix you're using. Using the wrong mixture can lead to starting problems and poor performance.

Exhaust: Sometimes the exhaust port or muffler can get blocked with carbon deposits which can stop the machine from starting. It's worth having a look at these and cleaning if necessary.

Adjustment Screw: For the fuel adjustment screw, it can depend on the exact model of the engine, so it's difficult to provide exact instructions. As a general rule though, you could try gently turning it all the way in (clockwise), then turning it back out (counter-clockwise) about 1 1/2 to 2 turns as a starting point. From there, you can fine-tune it based on the engine's performance. Turn the screw in small increments, waiting a moment for the engine to respond. The aim is to find the point where the engine runs smoothly, without any stalling or excessive smoking. Be careful not to over tighten the screw as this can damage the seat.

Fantastic thank you.

I took the carburetor apart again last night and cleaned it through. Took the fuel filter out also which appeared ok but wasn‘t really sure what I was looking for. Put it all back together today and it started and ran for a little while but after a squeezing the throttle a little bit it cut out. Started it again and it would tick over for a few seconds and then cuts out. It then wouldn’t start. With regards to the fuel/oil mixture I just follow what it tells me on the plastic mixing bottle which is a little confusing because on one side it says to fill up with fuel to 576 then top up to 600 with oil but on the other side it says to fill up to 500 with fuel.

 

[Swwils]

Fuel/oil mixture instructions can indeed be a bit confusing. However, it's important to get the mixture correct as using an incorrect mixture can cause engine problems.

As a general rule of thumb, many brush cutters use a 50:1 or 40:1 fuel to oil ratio, which equates to 20ml or 25ml of oil per litre of petrol respectively. This is what the instructions on your bottle are likely referring to.

So, if you fill up the fuel to 576 and top up to 600 with oil, you're creating a 50:1 mix. On the other hand, if you fill up to 500 with fuel and top up with oil, the ratio is different and likely not suitable for your brush cutter. Always follow the ratio recommended by the manufacturer for your specific model.

As for your cutter cutting out after squeezing the throttle, that's often a sign that the carburetor might not be correctly adjusted, especially if the idle speed is fine but it stalls under throttle.
It could also be that the fuel filter, despite appearing okay, is not functioning correctly.

The fuel filter's job is to catch any particles in the fuel before it enters the carburetor. Sometimes, these particles can be microscopic, so even if the filter appears clean, it may not be functioning properly.

In addition, check your exhaust. A blocked exhaust can also cause similar symptoms, especially if the machine starts and idles fine but then cuts out under throttle. Be sure to check the spark arrestor screen, which can get clogged with soot and carbon deposits.

Finally, if it's still not working properly after checking these things, it could be an issue with the fuel pump diaphragm in the carburetor. Over time, these can become stiff or cracked, and thus they stop working correctly.

Replacing this diaphragm could solve the problem, but it would involve disassembling the carburetor again. If you're not comfortable doing this yourself, it might be best to take it to a pro.





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[Tony 1]

Fuel/oil mixture instructions can indeed be a bit confusing. However, it's important to get the mixture correct as using an incorrect mixture can cause engine problems.

As a general rule of thumb, many brush cutters use a 50:1 or 40:1 fuel to oil ratio, which equates to 20ml or 25ml of oil per litre of petrol respectively. This is what the instructions on your bottle are likely referring to.

So, if you fill up the fuel to 576 and top up to 600 with oil, you're creating a 50:1 mix. On the other hand, if you fill up to 500 with fuel and top up with oil, the ratio is different and likely not suitable for your brush cutter. Always follow the ratio recommended by the manufacturer for your specific model.

As for your cutter cutting out after squeezing the throttle, that's often a sign that the carburetor might not be correctly adjusted, especially if the idle speed is fine but it stalls under throttle.
It could also be that the fuel filter, despite appearing okay, is not functioning correctly.

The fuel filter's job is to catch any particles in the fuel before it enters the carburetor. Sometimes, these particles can be microscopic, so even if the filter appears clean, it may not be functioning properly.

In addition, check your exhaust. A blocked exhaust can also cause similar symptoms, especially if the machine starts and idles fine but then cuts out under throttle. Be sure to check the spark arrestor screen, which can get clogged with soot and carbon deposits.

Finally, if it's still not working properly after checking these things, it could be an issue with the fuel pump diaphragm in the carburetor. Over time, these can become stiff or cracked, and thus they stop working correctly.

Replacing this diaphragm could solve the problem, but it would involve disassembling the carburetor again. If you're not comfortable doing this yourself, it might be best to take it to a pro.





ChatGPT may produce inaccurate information about people, places, or facts. ChatGPT May 24 Version

Thanks for your help. Just to cover all bases, I ordered a new spark plug as I noticed it was quite oily on the tip so for sake of a few quid I might aswell just change it. A new fuel filter purchased also and I'll check the exhaust when the other bits arrive. I'm going to empty the fuel tank and replace with fresh fuel and I found an online manual which if I've read right it says 25:1 mixture so I will try that ratio I'm now thinking, especially with your advice that it's not set up properly and maybe it never has been. I think it might not be getting enough fuel through. The reason I'm thinking is the cutter only runs with the choke on, it has from the day I purchased it which was over a year ago. As soon as the choke is closed even though the machine is warmed up, it just cuts out.