sarse wrote:
Can someone advise on my Hayter Harrier, started it today & straight
away it started puffing out loads of smoke & smelt horrible, the smoke
soon burnt off & mowed as usuall. When i came to restart it the pull
cord was very tight & couldnt get a full pull on it.As soon as i took
the mucky spark plug out & pulled the cord again it pulled nicely as
felt like it should.
I have unbolted the head & noticed the top of the piston has a large
round patch of thick gunky dried oil on it, there are also two (what i
think are valves) visible with the head removed, one of these is a
clean metal,the other is gunked up with wet oil, can anyone shed some
light on what might have gone wrong here as id like to repair it
myself (if i know what to replace)? Thanks in advance.

Had you tipped the mower before the problem occurred?