Nick no_bother@all wrote:

wrote in message ...
Nick no_bother@all wrote:
I have a Mountfield lawnmower with a Honda GCV135 engine. I tried to use
it
the other day and although it started immediately it wouldn't run at a
constant speed. It slowed to a stutter and then speeded up then slowed
down
and so on.
There is a linkage between the carburettor and a spindle projecting out
of
the engine casing. This is oscillating backwards and forwards. I know
what
it's connected to at the carburettor end but have no idea what the
spindle
is connected to inside the engine.

This is it (the speed regulator that is).


That's the speed regulator, there's a flap inside the cowling which
gets pushed by the flow of air as the engine speeds up, this closes
the throttle and (if it's all working correctly) should prevent the
engine from over-revving.


Please can anyone suggest what might be going on?
I've done the obvious things like renewing the spark plug, cleaning the
air
filter, checking for fuel line blockages. Next on the list is to strip
down
the carb. but I thought I'd post here first.

It sounds like fuel starvation, so double check the fuel lines first,
then I think your next move is probably what you said, there may be a
blocked jet in the carburretor.

It may also be worth cleaning out all the accumulated grass and gunk
that's in with the regulator flap too.

--
Chris Green

Thanks for that. Please can you give me a clue as to where the regulator
flap is?
I heve removed the petrol tank which exposes the magneto and a 'fan'. Is it
somewhere in this area?

See above, it's whatever is on the other end of the "linkage between
the carburettor and a spindle projecting out of the engine casing.",
the engine end of it will almost certainly have a flap or something
which is 'blown' by the wind from the magneto fins.

--
Chris Green