In message , NY
writes
I have a Flymo Hover Compact 350 mower which is not cutting as well as
it used to: it tends to leave clumps and sometimes I have to go over
the same patch a couple of times because initially it bends the grass
over rather than cutting it. This is for normal lawn grass with maybe a
week's growth since the last time it was cut.

I've had the blade sharpened. As far as I can tell, the motor is
running at full speed.

The only thing that is unusual about the blade is that it is slightly
kinked: the last few centimetres where the blade is sharpened bend
upwards by a few degrees (ie the tip is slightly further away from the
grass). Should the fact that the blade is not perfectly flat matter,
given that the height of the cut will be determined by the lowest point
of the sharpened part of the blade.

I had a couple of fairly cheap hover mowers, and on both of them, after
some use, the tips of the blades started to be bent slightly upwards. I
assume that this was caused by the constant pounding from hitting the
blades of grass - and also the occasional stone.

As it's the fast-moving part of the blade near the tips that does most
of the cutting, having the tips bent upwards allows the slow-moving part
near the hub to chew rather than cut.

Every time I took the blade off for sharpening, I made a point of also
bending the blade so that the tips were slightly downwards.
--
Ian