hello gvh, you want ngk br8hsa sparkplug, ebay has them for $4 shipped, scrappydogscooters. these 2t scooters use up sparkplugs, and need new plugs from time to time, I put in new plug at the 1st sign of any issues, like stalling at red light, hard to start, missfiring.
how many km's on your scooter? is it low on coolant?, you probably need to change it out anyway. if scooter has lots of km's or been awhile since run, probably needs full maintenance. do a search, or read the old threads for Super 9 and you will get all the info you need to get your scooter running great. cheers