Brush Cutter Fuel Feed

[yottie]

I have a two wheeled brush cutter (no sign of name I'm afraid).
Haven't used it for about 3 years but the grass now needs sorting before it gets out of hand.
This is a 2 stroke with the usual controls.
Filled up to three quarter mixture of petrol and oil, checked plug etc.
Problem is there is no sign of fuel reaching the carb.
The "manual" says to prime the carb 6 times, this has no effect.
Have had the rubber plug out containing three pipes, they are all clear.
It's acting as if the tank isn't airtight but I'm careful to make sure all is secure.
Help!!

 

[Burnerman]

I guess the primer bulb is see through?
It needs to be full of fuel ( you can’t over do the priming so pump away).
If there’s no fuel visible after a dozen or so presses, then the pump diaphragm in the carb isn’t doing it’s job.
Post a pic of the carb if you can!
John

 

[Tetrarch]

Is the priming bulb actually forcing fuel down the pipes?

I had a split bulb and a split tube on my Titan Strimmer - took me several hours to diagnose

Regards

Tet

 

[yottie]

OK. took the plastic front of the carb off.
The only way to see the actual carb is to remove it from the engine.(there is another plastic front on the carb.)
The pipes (3) from carb to tank are all clear.
Is it possible for me to check what's happening by removing the plug (surrounding the three pipes)
from the tank, then inserting the pick-up plug alone into some fuel to see if it pumps through to the carb?

 

[Burnerman]

You can do that - it’s the pipe with the filter on the end that’s the important one- and it’s worth checking the pipes for splitting at the same time.
These pipes often fail either just within the grommet, or just on the tank side.
John

 

[yottie]

OK. have removed grommet, with three pipes from the machine.
No leaks anywhere, the three pipes all OK.
Am wondering how the inlet pipe works.
There is an attachment at the tank end which is quite heavy,
have blown through it from the carb end, there is resistance but it produces
bubbles from the attachment when immersed in water.
It looks to me (as an amateur mechanic!) that the problem requires the carb to come off.
If this is the case what am I to look for please.

 

[lostinthelight]

Am wondering how the inlet pipe works.
There is an attachment at the tank end which is quite heavy,
have blown through it from the carb end, there is resistance but it produces
bubbles from the attachment when immersed in water.

That end is a weighted filter so it always falls into the fuel no matter what angle the machine is at.
The filter sometimes has a felt cover on which holds tiny amount if fuel so now you've had it in water it will need meticulously drying or water may get sucked into the carb filter.

 

[Burnerman]

Give us a pic of the carb once you have it off please!
John

 

[yottie]

Will do.John
Thanks

 

[yottie]

Have just got back to "fixing" this.
Thought I'd make sure of everything again before removing the carb
Good job I did, there is no spark.
Have changed the plug for manual test (laid on cylinder head)..no result.
The "user manual" (which is a slight exaggeration) is entitled vidaXL.com.
Have checked the HT lead, this shows a reading to the plug pin.

 

[lostinthelight]

Have you checked for plug sparking with the kill wire disconnected

 

[yottie]

I don't understand "kill wire".?
Have tried for spark with two separate plugs.

 

[lostinthelight]

I don't understand "kill wire".?
Have tried for spark with two separate plugs.

wire that connects the coil to on off switch

 

[yottie]

OK. I understand, yes am aware of it.

 

[Burnerman]

The timed spark on these is courtesy of a solid state coil called an igniter.......unless it is really old where it may have contact breaker points under the flywheel.
Not much you can do to it, so disconnect the kill wire and check for spark again......preferably in the dark as the spark is so tiny it's difficult to see.
The gap between the igniter and flywheel should be around the thickness of thin card - in other words as close as possible really without touching.
If you can show us an engine pic maybe we can identify it!
John