lawn Mower not collecting the grass cuttings

[PatK]

I purchased a secondhand lawnmower this year and have been experiencing problems with it picking up the grass cuttings. It just seems to block up and stall.

It is a Mountfield Empress 16.

It have been struggling to get it started and it's not running smoothly and emitting black smoke (I have been using "old" petrol - which I know is a problem - didn't know petrol can go off)

Any advise / help would be appreciated.

[labs]

I had the same trouble(I had a friend at Bartram Mowers)Is advice was:
1.Clean the spark plug )or replace with a new one
2.New air filter/in line petrol filter
3.Most important do not use from last year petrol.
Which i did now runs like a dream :D
Hope this is of help to you
regards