Find a long gentle hill and zipp down it. It will make your legs spin faster. Its a less full on version of how sprinters train 'overspeed' either behind a moto or off of a steep hill.
Raising the saddle might fix it but at the same time cause hell eleseware. Usualy the best starting point for a saddle is 89% of your tottal inseam. The fastest spinners on the planet are no doubt sprinters. They are known for running their saddles slightly lower than normal and further back.