Hi everyone,

My first post on this forum, so a brief intro: we're Brits living in northern France (Normandy) for the last four years, though hoping to return to the UK in the new few months.

I have a mower with a Briggs and Stratton XP40 mower which is not running well. This will be only its third year of use, and I've never had a problem with it until now. I used it for the first time this year a few weeks ago – no problem, seemed to be running as normal. I then got it out again last week and found that it wasn't running smoothly. I would say the engine seems to be "hunting" – almost like it's coughing slightly – it sounds at various points as though it's going to die but always manages to keep going. Two further symptoms: (1) puffs of black smoke are visible by the grill on the L/H side, and (2) it used an awful lot more petrol than usual when I cut the grass with it the other day.

I'm no mechanic, but have done my best to do the basics in an attempt to rule out obvious causes: I've cleaned the air filter (seems fine), taken off the plastic engine cover and cleaned round everything I can, and changed the oil. Doesn't seem to have made any difference.

One other thing I've noticed: when first starting the engine (even after only a few minutes' break in running), it seems to run nice and smoothly for maybe ten seconds or so before starting to cough and splutter again.

I would have taken it in for repair, but there's only one place in the vicinity and they have a 3 week wait! I'd be very grateful if anyone has any ideas or suggestions. (N.B. I've looked on the B&S site, but so far only found quite generic advice that hasn't helped me.)

Thanks in advance,

Rob