My 1999 312-8 had been giving me ignition problems and finally crapped out. Turns out that the magneto had gone south and a replacement did the trick.
I bought this one new and it has been my go to machine even though I still have my 1969 Raider 12. My big surprise was the amount of dirt inside the fan housing. I'm just surprised that this engine survived and did not overheat.
My Fall PM routine is to now include pulling all the tins and the housing to clean away the dust and dirt. (No mice or other critters that I could detect)
Bob