[Goldfinger]

I've tried to get started today, the shared rotavator on our allotments with no luck. 

There's fuel there, but no spark (plug out on lead, resting on body).

I've checked the manual on here, but can't find anymore info on trouble shooting, it just says to check the plug and gap etc.

Any idea where to try next?

[tadpole]

As with all petrol things, it matter the age of the fuel so I know said there is fuel in there, but how old it is? change the fuel, first, then check the spark plug, change it if you don't know what the gap should be/is, or if it's not looking at its best (either grey and dusty or black and oily. then check it is sparking (nice and bright). Then the earth lead. then and only then start to worry.

[Goldfinger]

The plug was changed just last year, so I thought it would be ok. Unless - due to it standing for so long, could that knack the plug, it still looks good as new?

When I first took out the plug it was 'wet', so I know the jet isn't blocked.

I then had the plug connected to the HT lead resting on the body to check for a spark while doing a few pulls but it didn't 'flash'.

And yes, I think I will have to change the fuel, I don't know how old it is, so I'll change it to make sure.

[smud6ie]

In my opinion there is no point in messing with the fuel if there is no spark!!
Make sure the plug is propery eathed as its often difficult to hold it tight enough against the METEAL of the engine.If in any doubt, twist a length of wire around the metal part of the plug anf clamp/trap the other end to the engine.
The other thing to try before things get more serious is to disconnect the earth/stop wire from the swich to make sure its not shorting/stuck in kill position
smud6ie

[Goldfinger]

In my opinion there is no point in messing with the fuel if there is no spark!!
Make sure the plug is propery eathed as its often difficult to hold it tight enough against the METEAL of the engine.If in any doubt, twist a length of wire around the metal part of the plug anf clamp/trap the other end to the engine.
The other thing to try before things get more serious is to disconnect the earth/stop wire from the swich to make sure its not shorting/stuck in kill position
smud6ie

Which way does the kill switch work?

Is the switch 'open' for 'go' and closed to stop the engine?

Can never figure which way it goes. 

[grendel]

it shorts out the points generally, stopping the spark.
Grendel

[Bigbadfrankie]

Does it have a G150 engine??

[Goldfinger]

Does it have a G150 engine??

Don't know, how do I find out what type of engine is it?

I there a number stamped on it somewhere to say?

[Gwiz]

The recoil housing will usually have the model on a sticker in the centre, but I'm guessing that if you can't see it, it's not there.
Stamped into the aluminum of the engine, below the cooling fins, you should find all the information,
Engine family, application code and serial number.

Just a thought, but have you checked the oil level? If it's a shared machine you can bet that everyone thinks that everyone else does it and in fact, it doesn't get done often at all.
Some Honda engines have a low oil cut out sensor. If the machine has sat a long time with low oil, the switch can become dry and stop the spark. Fill to the correct level, pull over a couple of times and off she goes again.
Worth a look before you take it all apart.

[Goldfinger]

Low oil cut-out switch? The rotavator maybe a little bit too old to have one of those... 

It looks as basic as....

Also, what about if the magneto 'faces' are rusty, can that cause the lack of spark?

But the only way to check that is to take off the flywheel! (Doesn't it?)    :blink:

[nuzuki]

Take off the air filter and pour a little petrol into the carb directly. If you have a spark it will start this way. Ive used this method tons of times on old garden machinery/mini moto's and even cars.

Other than that as suggested already, check its not in the kill position or that the kill switch has broken

Do a continuity check between the plug and the end of the HT lead (spark plug lead).

Just think "fire triangle" i.e you need air, fuel and spark. Take one of these away and no fire.

Hope this helps 

[Gwiz]

Any chance of a few photos?
"A picture paints a thousand words" and all that..... (And I'm useless at model numbers, and too idle to look them up on google)

[smud6ie]

any numbers where first file shows?

coil test and air gap near bottom of table in second file

[Goldfinger]

I'll get some as soon as then, cheers all for the help.... so far 

[Goldfinger]

Had another go tonight, with a new spark plug but still nothing!

Had a meter on the kill switch, it's ok...

But I have come away with some photos, (and an engine swap is now springing to mind  .....)

 


This number says F300 - 1001606



This one says G150 - 1429759