Husqvarna 545RX brush cutter starting but not accelerating

[spudulike]

2 hours ago, Dean Lofthouse said:

Try getting a carb kit and replacing this, sorry I don't know the name for it but it is a one way valve for the fuel, The "flappers" on it get worn and the machine displays the exact symptoms you are experiencing. I've changed loads and it's done the trick.

It is the pump diaphragm and those flaps do tend to perforate over years of use.

If the machine is low hours, it is unlikely to be this. If it is well used..........

Edited January 1, 2022 by spudulike

[spudulike]

The symptoms you give are that the machine will idle OK which means the carb is providing enough fuel for low revs. When you open the throttle, the carb is only giving air and not an increase in fuel so there is an issue with fuel delivery through the carb so...if the machine is pretty new.....ADJUST THE CARB....a bit of anticlockwise on the H screw should do it.

If the machine has seen lots of action, pressure check the fuel line, change the fuel filter, check the gauze strainer and pump diaphragm, clean the air filter and adjust the carb afterwards. This should fix it.

Much depends on how much use the unit has had. Little use leads to adjustment of the carb. If it is old and well used, the diagnosis slides over to a fuel system overhaul.

[adw]

It may not be so easy to adjust the carb as they will have anti tamper screws, there are two different types dependent on age, one type will be a spring loaded plate with a spline on the screw head, the other is an aluminium cover, this is not so easy as it needs to be removed to access the screw underneath, this is best left to somebody with a little more knowledge of this carb. If the machine has done a fair amount of work I would be more inclined to say the metering diagram had gone hard and lost convolution.

[spudulike]

Convolution.....A mathematical operation on two functions giving rise to a third.....have you swallowed the dictionary or just getting over excited at the TV premier of Downton Abbey tonight!!

Happy New Year BTW

[adw]

More into Emerdale at the minute, murders galore.

[Stubby]

7 minutes ago, adw said:

More into Emerdale at the minute, murders galore.

Meena is a piece of work !

[adw]

She sure is, all good stuff.

[spudulike]

I think the plot is a bit....convoluted