This is my 2-cents...but I thought this was already well known?
There are advantages and disadvantages with both types of engines. I think two strokes are easier to repair imo. There are no valves to speak of and therefore, no camshaft. So, no hassle with valve clearances or bad sealing, which happens when carbon deposits build up around the valve faces and on the seats, or when the valve guides get sloppy. Because they dont have as many moving parts, this makes them cheaper to maintain and repair. This should translate to a longer lifespan.
A huge advantage is, they're more compact and lightweight than their 4-stroke counterparts. Meaning, they are well suited to handheld power equipment like trimmers, hedgers and chainsaws. Furthermore, they don't have a huge sump just to hold oil for lubricating the internals. You don't ever have to worry about a 2-stroke seizing (when you turn it upside down). A 4-stroke will be damaged from oil starvation if you try this.
Disadvantages are, they burn oil, smoke, run/idle rough and are loud. Especially after the piston and rings are well worn. They are also more difficult to tune. Optimal running can require adjusting the fuel to oil ratio depending on weather conditions. Carby needs similar adjustment for hold vs cold conditions.
