For those who get short life out of a SkyTec, or any other permanent-magnet starter, pay attention to the manufacturer's warnings about duty cycles. This is from the 149NL maintenance manual:
The motors in these things are much smaller than the old Prestolite starters. They are permanent-magnet affairs adapted from modern automobiles, and are a high-speed motor, geared down to crank the engine. Modern cars start easily, as they have all the electronic stuff to make fuel and ignition just right the first time, and these starters are not usually trying to push huge pistons around. An O-360, 360 cubic inches, is 5.9 litres, 5900 cc, big for any modern vehicle.
And they are typically seven or so pounds lighter than the old starters. That seven pounds could absorb a lot of heat. And that seven pounds was all in the starter motor, too, not in any gearing and extra housing. That little PM motor will get real hot real fast. It has no cooling other than through the case, and since the armature is the thing getting hot, not any field coils, the heat has to find its way out of the armature and into that case and from there to the air. Takes time. The nice thing about these starters is their good cranking speed, making that engine wake up faster, as long as the pilot is intelligent enough to manage the fuel and isn't trying to start a seriously cold-soaked engine.
So you can't just crank until the battery gives up. That starter is likely to give up first. Seems to me that SkyTec provides a panel decal instructing the pilot in the limitations. Like a lot of installation data, it gets ignored.
