[ben]

Check:
- The pressure pad and plate are clean.
- The pinch roller is not cracked.
- The capstan shaft is not wobbly (bearing trouble)
- Nothing is dragging on the capstan flywheel. ISTR a felt lining which may have come loose.

The main problem I find on these is hardened grease on the linkages which engage the clutches on the spool tables and also act as brake. You usually find a kind of yellowy tar all over the upper deck plate. The (largely inaccessible!) area below the joystick is always sticky too.

There are a couple of raised metal 'ramps' between the spool tables and the headbridge area which are how the clutches are shifted up and down (a most unusual design, heaven knows how they manufactured that to the necessary tolerances!) Backtension can also be affected. I suppose that could cause wow and flutter in your case, but I would also look elsewhere. I even had one fairly recently where the record lever would not lock down, there was a sticky linkage sandwiched between upper and lower decks.

A drop of light oil in the motor's upper bearing may be needed. As you have found, it is a good idea to clean the pulley of all black gunk.

A video might be a good idea if this continues after the above have been checked.