On Mon, 22 Jun 2020 06:16:30 -0700 (PDT), Lee Nowell
wrote:

Hi All,

A quick update on my mower - thought I would start a new thread in case the specifics helps someone else in the future

The mower started first time - I was amazed. However... The engine runs very unevenly. It doesn't sound like it is likely to stall but runs what I would call lumpy with an uneven rev.

When you say 'runs / unevenly' do you mean across the whole rev range?

Many mowers have a simple flap regulator to stop the engine from
stalling. It controls the throttle via a flap the sits in it's own
cooling air flow, generated by the fins on the end of the magneto /
flywheel.

When you set the throttle it is set via this 'regulation' (using a
light spring usually) so that it would try to increase the throttle
with both at tickover and under power, should it be required.

So, this means they do seem to 'hunt', at tickover especially as the
feedback loop is quite slow.

If you give it some throttle and actually cut grass with it and it
does so whilst holding a reasonably (but not completely) steady RPM
I'd say that was ok? ;-)

Cheers, T i m