After beating the Ecruteak Gym Leader Morty, you go to Olivine City and go to the Lighthouse to find Jasmine the Olivine City Gym Leader there, talk to her and she'll tell you what she needs. Head to Cianwood City and challenge Chuck the Gym Leader there and make sure to get the Potion for Ampharos there as well before heading back to Jasmine.
The fourth gym leader in Pokemon Soul Silver is in Ecruteak City.
in his gym
the 16th gym leader is:Trainer Blue
go to the Pokemon gym
He is on Cinnabarr Island.
you dont
the 15th gym leader in soul sliver is blaine and he uses only fire type pokemon
Ghost Pokemon.
Blue, the last gym leader in kanto region
Morty is the Gym Leader of the Ecruteak City Pokemon Gym.
The last gym is in viridian city
The Gym and Gym leader is in the bottom left of the city near the Pokemon center.