Just some things to look at when you are doing the maintenance on a treadle.
>Start with the treadle plate pivots. Make sure they are clean of old grease, not too loose or too tight. Then grease them.
>Then take the pitman rod apart at the bottom. In the big nut that fits into the treadle plate I've seen a spring loaded plunger in the bottom. This part allows you to keep tension on the pitman shaft without having to crank it down way too tight. Make sure it's clean and free then grease it.
Then adjust it so there is no movement between the shaft and plate, but no binding either.
>Big wheel pivots. Check them as you did the treadle plate. Adjust them so the wheel has some side to side movement, but not too much. Grease them.
>Big wheel crank bearings. Clean them and grease them.
For the grease I use a high shear chassis lube. Yes it's thick. Yes it's messy if your not careful. Yes, if you use the treadle a lot you'll have to relube it occasionally. It may fly in the face of what you've read, but these points on the treadle mechanism are high friction points. Just oiling them is not enough in my opinion.
My #2 Singer 66 treadle is so easy to treadle I can run it as fast as some of our electric machines. It can be started by foot pressure on the treadle plate most of the time.
My #1 Singer 66 treadle is also easy to treadle, but it wants to stall and you have to coax it with the hand wheel to get it started. I'm working on it. I think it's the pitman shaft area that's the problem.
Joe