I work on the old Fairbanks Morse starters on my saws of which most vintage saws use. If the starter cups are not worn out too far the most common problem is the starter pawls not extending when the rope is pulled. The friction washers and the spring pressure has to be correct to cause the pawls to extend when the recoil revolves. I count myself lucky as I bought out a saw repair shops left over stock of starter cups, pawls washers etc and have not had to look around for any lately. They are out there but you have to look for them, the old standby eBay and some of the eBay stores have some. I will measure my 5020 and see if I have spares, the bolens I don`t have one to measure but I have a few Strunk saws I will also measure . Pioneerguy600
+1 on the friction washers.
I fixed mine on an 070 2 nights ago. I assumed that I needed a new cup and pawls, and was about to order them from Cheap Stihl Parts...but then I decided to fiddle.
The pawls only extend if the friction washers are gripping the assembly hard enough. If there is not enough friction, then they will only come out if you spin it really fast - and will lead to the "catching and missing" that we feel.
You need a friction washer on each side of the pawl assembly - these will be made of "friction material" - sort of fibrous stuff. I was missing one, and made a new one out of leather - it works fine. There will be other washers separating all of this from the rest of the starter - look at an IPL. Anything missing = no friction = no pawl extension = no starting.
A quick test. Take the starter off and pull the cord slowly. If the pawls don't extend, you have a friction problem. If they do extend, then you have a pawl/cup problem. On an 070 the leading pawl needs to be sharp - ground to a 60 degree angle. The get blunt with use, and may need cleaning up.