old sewing machine pedal?

OK. I'm stumped.

I inherited a lovely old brother sewing machine from my gran ( two of em actually, but one problem at a time...)

After a little playing and a lot of cursing, she runs beautifully, but with one small problem. She always runs at full tilt max speed.

I would think its the foot pedal, so I took it apart. Its an old wire wound rheostat with a brass wheel that contacts the winding to provide a varied resistance it seems. At first, i was getting nothing untill the pedal was fully pressed and the contact wheel hit the bypass plate at the bottom of its travel.
After some cleaning and some more cursing, the multimeter reports that I am getting a nice variance between 0 and about 10 ohms.
Reassemble and try again, and this time she kicks in at the beginning of the travel. But still at full speed.
I read online that the capacitor is often the problem, so I removed that, and still the same.

Run out of ideas now.
Anyone have any thoughts?