"Theo Markettos" wrote after
Bob Hobden replied
Sounds like fuel starvation caused by dirty carb, dirty petrol filter,
dirty petrol tank, carb float not floating any more but stuck.

Took out the spark plug and it was indeed covered in soot, and the air
filter was filthy too. Cleaned both of those as best I could and
replaced,
didn't have much difference. I'll see if I can replace the fuel - just
need
to find a funnel. I discovered it was four stroke (it even says on top,
d'oh) and there was a small oil filler cap hidden in the muck - seemed to
have oil in it.

Two further things to try...
1. Try to start it and then remove the plug, if it's very wet then you
haven't got a petrol starvation problem, quite the opposite. If it's still
totally dry the fuel starvation idea is confirmed.

2. Remove the plug and rest it on the side of the engine so the screw bit
touches metal, connect to plug lead and try starting again and see if there
is a nice blue spark across the little gap. If not you have an electrical
problem.


The engine on top should have a name on it, normally Briggs & Stratton (4
stroke) or Tecumseh (either) or if it's a more expensive mower a Honda (4
stroke). If it doesn't say B & S or Honda it's more than likely a
Tecumseh
probably with another name on it though.
Take a look at the following and see if you can see your engine, then
look
for instructions and troubleshooting, you may even be able to download a
manual.

Tecumseh rings a bell - I'd have spotted if it was the other two. I'll
have
a look on the site to see if I can find any instructions.

Their main UK spares place is not far from me in Commercial Road, Staines.

My guess is it just needs a service, if it's a 4 stroke then carb'
cleaned
out, and if dirty then petrol tank cleaned out *, then check/change...
new
plug, new oil, air filter, if it's a 2 stroke then everything but the
oil.
* look also for a petrol filter, it may be blocked with crud too.

Are such things easily accessible (have found the oil, the petrol, the air
filter and the spark plug orifices) or is it usually a 'unscrew every bolt
you can find' job?

Not always. I think you can download a Manual from the Tecumseh web site,
worth a look.
I still think the main contender is that the carburettor is blocked/ full of
crud and simply needs taking apart (carefully in a clean area) and cleaning
(float chamber & jet).
If you damage the paper gasket then carefully cut a new cardboard one from a
cereal packet and make sure you clean the metal surfaces of any bits of the
old one. These tiny carbs can be a fiddly to work on so do take it somewhere
clean and well lit so you can see what you are doing, and treat it carefully
they have very fine tolerances inside.

--
Regards
Bob H
17mls W. of London.UK