I've got a 25 year old chainsaw that's had a ton of repairs, been rebuilt (by me), has stuff that doesn't work and odd things that aren't right. But it's my "big" saw and I do forest management, so I do need this thing. Lately, I burned out the clutch. Completely my fault and a learning experience (don't do that again). Anyways, I first bought a replacement clutch spring ($7) as the saw kept the chain always engaged. With the new spring, the thing slipped like crazy. I ended up buying a new clutch ($50) and it worked great for about 1/4 tank of gas, then started slipping. I gave up and put the saw on craigslist.
Well, this changed my way of looking at things. I figured I have nothing to lose as it's advertised with a slipping clutch and all the other things that aren't right. I pull out the old clutch from a box. Pull the new one off. Sand down the inside of the drum and then install the old clutch. The way this works, that spring keeps the shoes from engaging until the saw motor is spinning fast enough. Since it wasn't engaging and I got nothing to lose, I put in a screw driver and pull the spring to loosen it up. Put the saw back together and what do you know. It works. I've taken down one tree with the saw and gone through a couple tanks of gas cutting up the wood to firewood size pieces. The thing is working great. Still has all the other quirks, but I can live with them all. Pulled it off of craigslist and put off my purchase of a new $600+ replacement saw. In the end, I sort of wasted $50 on a new clutch, but it was worth it to learn how to get the thing going once again.
Next project is going to be a "little" saw that I rebuilt years ago but never could get running right. I know there's an air leak somewhere but really didn't want to pull the thing completely apart again. I bought a replacement saw about a year ago, but you know, having another running saw would be really good to have.