I have heard those ones (haven't had anything to do with repairing them directly) will strip the starter if the person doesn't follow the 'pull slowly until resistance is felt' clause in the manual.
It should be common sense to treat all pull starters that way. Be ginger and feel for it to engage before pulling briskly. Pulling hard from the get go is like putting an automatic into drive or reverse while the engine is revving, you just don't do it.
It's amazing how some people treat equipment
