The Pfaff 131 is a very rare bird in these parts. I see 130s all the time, 30s sometimes (there are TWO currently for sale in my area, unusually), and the smattering of later Pfaff machines, mostly from recent years. The 131 is often described as the straight version of the 130 but there is one significant difference: the bobbin faces left, rather than forward. This requires the user to lift the machine each time the bobbin needs changing and this (for myself) requires the machine to be in a table rather than a case, as is this one:
Another significant difference is that the 131 has a full rotary hook. It can be considered the full rotary 30, I suppose.
The seller is a really nice guy who didn't really know anything about it. The machine was not terribly dirty other than the usual grime but I found leaves and seeds from cedar trees inside the case and on the machine.
Note: Unless your garage is heated and equipped with weather stripping around the doors, etc. and is preferably insulated, a garage is not a good place to store a sewing machine or any other similar piece of equipment. The best place is inside a house, warm and dry.
I oiled it and it runs extremely well: this 131 is very smooth, fast, and strong. It's similar enough to the 30 that a side-by-side comparison is probably in order where I'll compare SPM, control of length, etc. Speaking of which, the length control on this machine is unusually accurate, as there lines between each numbered length setting indicating, say, 3.75 or 2.25. The light is plastic but not the more typical rounded lamp style and I prefer this one.
Cosmetically, it has a few dings but it's in very good shape overall. The craquelure in the paint and varnish is typical of certain machine of this age and this is minor compared to some of the Pfaffs and Necchis I've seen. The left spool pin is bent probably beyond repair so I'll pry it out and replace it soon. The motor is quiet, the hand wheel is very smooth and light (and stops instantly thanks to its small mass) and while the rheostat pedal is as expected, it works. The nickel is all in great shape and even the bobbin winder tire is fairly new. Someone took care of this machine along its journey.
So there it is, my very first 131. Fast, smooth, and an excellent stitcher. The seller said he got a bunch of responses after mine so I'm glad I was quick on this one; I know I'll not see another of these machines in a long, long time.