Brush Cutter no spark

[yottie]

My brush-cutter is showing no spark. Have tested all leads and the only thing left is (what appears to be) a small transformer. This has the following letters on it...XIUTE, the machine is about 2-3 years old, used very little. Am I correct in assuming this little thing is the culprit and,if so, where to buy a replacement.
many thanks

 

[Burnerman]

The part you mention is called the igniter and produces an electric current when the magnets on the flywheel pass by it.
I have to say, igniters are pretty reliable so before you part with the cash, remove the small black wire that is the ignition cut out switch.....bypassing this switch removes it out of the equation.
Next, the spark may be extremely minute and difficult to see so attempt to get a spark by looking at things in the dark - remembering that the plug body must make contact with the metalwork of the engine. Also, do try a replacement plug!
You don't tell us which make of machine this is?
John

 

[yottie]

Thanks for that. The machine doesn't have a name plate on it! Have browsed online and similar ones rejoice in the name of Vida XL and Stroke, the engine is 52cc.
It has an "ignition switch" with a key to activate. Have checked all leads with a meter, they are OK, the key switch is OK, have tried a different plug, no spark.
I bought this about 3 years ago, have used it about six times, it was stored in a shed over winter, tried out 3 days ago, no spark from 2 different plugs.

 

[Burnerman]

It sounds very much like Chinese in origin.....check out GHS Ltd for spares, in particular Taurus / Silverline ignition coils. You may just get lucky!
52cc seems bloomin' big for a brush cutter.
John

 

[yottie]

OK. have come across what seems to be what I need at Chinatera Ltd for £7.19
Watch this space!

 

[yottie]

Have now fitted a new coil, the engine fires up for a short time then stops!
I am pretty convinced the problem is with the fuel feed (there's not much else!).
There are 3 tubes emerging from the plastic fuel tank:
One is black plastic, goes into the carb, have peered into the tank and it seems to have a pick-up (filter?) on it's end.
The other clear tube goes into the tank from the carb (overflow?)
The remaining clear tube comes out of the tank for 3 inches and has a plastic fitting on the end. (breather?)
All three tubes go into the tank via a black grommet, which leaks fuel where the tubes emerge.
There were no instructions with this machine.
Can I assume that that the 3 inch tube does the breathing, and that the tank screw cap needs to be tight.
I don't like the fuel seepage from the grommet but how could I stop this?
Many thanks

 

[Burnerman]

The pipe with the filter is the fuel to the carburettor, and the other is the return when you pump the primer bulb.
New pipes with grommets can be had from GHS Ltd but do check the diameter needed.
Can you keep the machine going by juggling with the choke, just as the engine is about to stall?
John

 

[yottie]

Thanks BM, am inclined to go for a new tank with fitments, but what is the short pipe with the end attachment for,
I don'st see one on any of the pix ?
(can I upload a small pic on this Forum?)

 

[Burnerman]

Sorry, I missed that one.....it will be a breather.
Are replacement tanks available? Previously I have used a two pipe grommet and then drilled another hole for the breather......but you need to get the pipe diameter right to avoid leaks.
John

 

[Harry Bloomfield]

One is black plastic, goes into the carb, have peered into the tank and it seems to have a pick-up (filter?) on it's end.

Brass? Heavy, at the end of a floppy bit of pipe, so it always falls to the lowest point in the tank, wherever the fuel is.

 

[yottie]

I'll try the new grommet way.
Thanks HB, love your emblem!

 

[yottie]

I don’t know if this is significant but, after fitting the new coil, the engine (after a few pulls) seemed to “back-fire”, the starter cord was actually snatched from my hand and wound itself around the carb.

I tried again, the engine fired up, ran at high speed for 15 seconds, then cut out and refused to start. I removed the plug, it seemed a bit dry.

 

[Burnerman]

Nothing wrong there as the timing is fixed....just show it who's boss!
It needs a carburettor service as the fuel isn't reaching the carb in sufficient quantity. Inside the carb you'll find two rubber diaphragms and a fine gauze filter - its worth replacing the diaphragms and blowing carb cleaner through all the tiny drillings and gauze.
John

 

[yottie]

Am awaiting delivery of an assortment of pipes, one with a grommet and TWO pipes only coming out (allegedly for my machine) from China.
Looking forward to these! In the meantime can I ask, as the tank is below the engine, how does the fuel get up there. I know the initial
supply originates from the primer bulb, but what force gets it there afterwards (engine down-stroke ??)
many thanks

 

[Burnerman]

A curious engine indeed, the two stroke.....fuel / air mix enters the crankcase as the piston rises......as the piston descends the fuel mixture is forced through transfer ports from the crankcase up to the combustion chamber where it is burnt. However, not all of the fuel manages to get to the combustion chamber - as the piston begins its descent a small charge is blown back into the air cleaner.
Its these pulses of pressure changes that allow the two stroke carb to continue working, once it is flooded with fuel after priming. Some carbs actually have a separate connection to the crankcase (larger machines usually) which facilitate things.
If you look at a two stroke carb (barrel side) you'll likely see a small drilling that allows a pressure pulse through to the carb......hence the need for a good gasket condition here.
The same really applies to a four stroke engine with a similar carb, actually - but on these the vacuum created with the piston descending and the inlet valve open is rather more constant.
John