Surge is much easier if you can use items, because both his Pikachu and Raichu have Thunder Wave and Double Team.
Considering that you have 3 team members weak to electric, you really only have 3 options for the fight, and they should all be at least L26 to make it easy (unless you're playing with a level limit), especially because Voltorb has Sonic Boom. His other moves aren't really that strong, considering that he only has Shock Wave, Tackle & Quick Attack to choose from, although from memory, Raichu hits REALLY hard. If you're not playing on set mode, I would advise you use Charmeleon/ Mankey first for Voltorb, and Gloom (as your Oddish will be) to tough it out for Pikachu & Raichu. However, the best strategy will be try and catch a ground type and spam the most powerful ground move, which you can do at the Diglett Cave if you haven't knocked out your encounter there. Diglett also evolves into Dugtrio at Level 26.
Considering that if you heal your paralysis Surge will just use T-Wave again, leave your Pokemon Paralysed until you're sure you can take his current Pokemon out.