On Mon, 3 May 2021 17:40:53 +0100, Chris Green wrote:

snip

all my saws have been 2 stroke
power to weight, mate.

It's not just power to weight ration, lubrication of a 2-stroke is by
the oil in the fuel. It's more difficult with a 4-stroke, you have to
make certain somehow that oil get's distributed around the engine
regardless of its orientation.

That's why many of the newer / better bits of kit are a hybrid, they
are 4/ in that they have conventional valves but still use a petrol /
oil mix for lubrication.

Most small 'domestic' petrol strimmers and similar machines are still
2-stroke, more for the lubrication issue than weight I think.

But may be going more 'hybrid' as the emissions and noise are
restricted.

Stihls '4-Mix' range are such.

https://blog.stihl.co.uk/stihl-4-mix...ogy-uncovered/

Our local council 'verges' crews have them and they are distinctive by
the sound of the lower revs used / available / needed.

Cheers, T i m