Quoted from Kingmiwok:
A few questions...
Any advice on the scraping issue? Put another washer under the diverter? Is it OK to pull the diverter fairly tight to the table by adjusting the set screw? Put some dry lube on the diverter shaft?
Also, what do I do about the scrape itself? Leave it? Fill it with something? I don't care much about the looks, you can't see it when it's assembled, but I don't want it to cause other problems.
Welcome to the club and to the world of owning a.pinball machine Hope you find fixing things satisfying.... Because you'll end up doing it alot
First things first, if you don't have it already, go to ipdb.org and look up Johnny Mnemonic. From there, you can download the manual. An exploded view of the diverter assembly can be found at 2-22.
Which leads to my second point. Never assume when you get an old pin that what you are looking at is right. Especially if the machine was ever on route. Ops came up with all sorts of creative ways to fix problems, and a lot of times, in the cheapest or easiest ways possible. Sometimes, these 'creative" solutions worked great.... Other times, just hacks to get the machine back to earning as quickly as possible. In your case, that applies to the metal washer you see on your diverters. That should not be there. There is a metal drive arm piece with a set screw that protrudes though the playfield. The nyliner (the nylon washer thing) should fit right into that and the diverters should rest right on top of that, tightened in place with the set screw. The metal washer was probably just added to create space, must creates a metal-on-metal movement situation, which as a general statement is not a good thing. Remove the metal washer, set the diverter flush to the nyliner and tighten the set screw. Problem solved. If there is still play in the diverter at that point, the nyliner may be worn out or not fitting snug. Those things cost about a buck to replace.
Third point: avoid lube of any kind unless specifically called out in the manual. Generally, you will only use lube/grease in the gearboxes and around metal bushings and where metal-on-metal action is required. In the case of JM, this is only in the gearboxes, metal bushings and the x/y screw rods of the glove assembly. Lube works its way into stuff and should not be used elsewhere unless you want to create other problems. In any case, avoid dry lube. That sh&*, especially if applied too thick, turns to a powder dust that can really dirty up your machine...which then causes wear.
Last, what to do about the sratches/gouges in the playfield. The simple answer is that this all depends on you, how much you care, and what you plan to do with your playfield. Sounds like you are a player and don't care as much about having the scratch so much as you don't want it to get worse. If that's the case, clean it out good, fill it with a wood filler of sorts, sand it smooth (don't sand paint/diamond plate off the field around it, paint over it (if you don't want to see it as much, and slap a small piece of mylar over it to keep it from getting worse. There are a million threads on pinside about repairing playfields and gouges..... Read up on those. If you don't care at all, you can just fix the diverter and play. Those spots aren't in super high-traffic areas of the playfield, so with the diverter fixed, it probably won't get worse anyway so long as the machine is clean and you are using good/new balls (which I recommend you get anyway, if they are not relatively new, since they get pitted and worn over time).