I know very little about the older Powersharp system, but it is supposed to be very different than the current Powersharp offering. The earlier version was not very well received. Search Powersharp on here and you should find the thread discussing it.
The old Powersharp you have on that S25CVA probably won't cut very well, but may be worth something as a collectors item since most owners threw theirs away long ago and they are now hard to find as a complete system, I believe.
The original Oregon powersharp chain designation 91TS (circa 1980) worked fine and sharpened good when used with chainsaws equipped with rotating round sharpening stone system - eg. McCulloch mini-mac series, Poulan Micro series, etc. The problem was with sharpener systems with curved stone shaped like the current Oregon sharpener stone. You had to move the stone lever sideways back and forth to get a consistent sharpen, plus some ham-fisted people thought that if a little stone contact with cutter was good, then a lot of contact would be better and destroyed their chains - also the glued bond between stone and backing lever was not the greatest and the stone or pieces would break off. McCulloch sold a great many powersharp equipped saws at the time. Sears felt that it was such a good feature that virtually all their saws were equipped with powersharp chain - at this time Sears sold a lot of chainsaws.
91TS chain would cut faster than any of Oregon's other mini chains at the time. The
problem was the
very high kickback from the 91TS chain - it would not meet the 1985 UL kickback standard for consumer saws (or for that matter wouldn't meet standard for professional saws under 3.8 cu in either). They had no option but to cease selling 91TS chain.
At a later date Oregon introduced 91LX powersharp chain with a very long bumper on drive link. Evidently the only testing done by Oregon was kickback testing. This chain was crap - it didn't cut as good as 91TS, but it's major problem was that after you sharpened the chain , you couldn't cut wood. They screwed up the cutter geometry so that the stone sharpened the cutters and depth gauge to same height.
Needless to say, this chain was not very popular and gave powersharp chain a bad name.
Oregon finally figured out how to correct cutter geometry and made bumper on drive link much smaller so that it did not interfere so much with sharpening; and from photos it appears that the curved stone is offset to bar nose radius so depth gauge is not eliminated during sharpening. Oregon tried to get the saw manufacturers interested in their latest design but wanted to sell the stone and plastic with chain to them at too high a price. No interest so they are selling it to retailers - retail price much more that should be.
