DjTy; Were thawing out up here in" TEXAS" but I will guess that it not be for long ( 34 degree's).,,, Try this: the motor has a set of brushe's that can collect a film of salt and corosive soap dried on the armature,,,, causing a problem with the electrical path,,, on the motor"s abilty to turn.
They make a electrical contact cleaner in a aresol can. It evaporate's fast and will flush the build up from the brush contact area if you can find the top of the motor tower,,,,,,,,,( reptangilar can hole ) where the plate with two lomg bolt's cover the end that stick's up and apply it internaly with the little plastic tube that come's with the can or some time's compressed air will clean it off enough to make it work these motor's were rebuilt with kit's all in the past so try this with a little
( bumping) it should start working again. frosty fingered Mike
,,,,EDIT ALSO CHECK THE GROUND - WIRE,,,,
IF NOT SEE IF IT IS (BADDLY GROUNDED) WEAK, ADD TEMPORARY GROUND TO CASE.,, WHEN RUNNING IF SPEED PICK'S UP AFTER THIS.,, IT MAY BE CORRODED INTERNALLY BEGGING YOU TO TAKE IT APPART AND INSPECT.
ALSO IN THE MEAN TIME WHILE YOU ARE WAITING FOR THE "CURE" USE
RAIN -X WINDSHIELD TREATMENT BRRRR IT'S COLD MIKE