AH! I had this problem on a much older Olympia portable. But the problem is could happen on the later models. What was at issue the older Olympia, was the escapement rack - the saw-toothed component that sits on the bottom of the carriage that engages directly with the escapement. I took it over to John's house, and he eased off the screws holding the rack on the right of the carriage, and slipped the rack up a tiny amount. The problem instantly disagreed, and the typewriter not works flawlessly. I suspect that there's metal burring that is building up in the teeth, but that doesn't really ring true. None the less. I have had two Olympias of its vintage that have responded in the same way, so i'm guessing there may be a common cause. That white SM3 is a stunner though!
I'm not really sure how to apply that repair to the SM3s...it sounds like that would fix the problem but I don't know how to go about it.
I'll get into one tomorrow, and send some photos.
*the problem could happen.Sorry, dodgy english monday here.
Nice looking SM3. I don't remember what I did to get the slow spot out of my SM4. The story behind my SM4 is so long I am still working on the typecast for it.
OK, binding carriage fix for Olympia SMs is here. Slacken both screws then retighten just so they nip. Then slide the carriage to and fro, make sure there's not too much play (there may be some if the bearings are unevenly worn or if there's a bend in any of the carriage rails).
Should add to the above that I was trying to fix excessive play, not binding. But the same principle applies.