I have a power torq 2 stroke from I think 1994 I still sometimes use, still cuts very nicely and runs no problems at all... Bunnings Victa Super Mulcher I have from 2015 is no better than the 1994 Victa!
That's why I thought better of Victa than to be using cheap rebranded stuff.... I can see the 1994 era power torq still performing well in years...
Power torq's are good for 30 to 50 years.
The problem is the engine was designed to be very low maintanance so most get no maintanance.
So they get slow to start, then difficult to start then impossible to start when instead of spending $ 90 on a full 20 year service they go to Bunnings and buy a new $ 500 4 stroke mower.
One of my fun things to do is service someone's "old back up" Victa to come back and find the Victa at the front of the shed being used & the Briggs in the back for back up.
There are 5 x O rings that go hard and need to be replaced every 10 years or so, particularly the one between the manifold & the crankcase and the one inside the pull start on the shaft, not the crankcase seal which should be replaced whenever you remove the pull start, same as the primer plate O ring.
These both leak air making the mower hard to start.
Lean the mix to between 30:1 & 40:1 if you use 2 stroke oil and the smoke will all but go away and the engine will run a lot better.
Once the PVC air & fuel lines go hard they also should be replaced ( 5-10 years ).
The plastic carb never wears out but occasionally you need to fit a washer under the cam if the engine is over reving.
Diaphragms go hard and should be replaced every 20 years which is about the real life of the air filter. along with both of the diaphragm springs.
It is real fun to watch the faces of the sceptical owners when they pull the cord & the mower starts before they get to the end of the chord, just like it did when it was new.
The swing back blades put no shock loading on the crank so crank bearings & oil seals never need replacing unless it has been under water and crankshaft never bend.
THe most common problem come across is a buggered thread in the carb because idiot owners continually pull the primer plate off for no good reason other than the fact that the main jet is there in front of your eyes.
Much like dissabling the seat switch just because it is there in front of your face.