Like Tartan mentions, the pedal might need a bit of adjustment. Another thing that's very common is the need for more cleaning and oiling. If it's been stored away for a while, bit might need a bit of effort to get it running smooth again. Sometimes there are noticeable improvement after cleaning and regreasing the motor. Make sure the motor belt is clean, as well as the groove in the hand wheel and pulley; oil spill is common too.
I like the original motor and pedal and keep them. They are just as good as the replacement and with a bit of service run like new. Sometimes you can add grease to the wicks in the motor with out any furtehr; but on some machines the grease can be dry and clogg up the wicks. One or two drops of oil can soften the old grease and reach down to the bearings, but be very careful, only one or two drops literally. If oil dribble along the motor axle it will ruin the motor.