Starter runs, but will not engage......

In 2012, I converted a Swisher fence weedeater, by adding a starter. I had help here getting me the part numbers I needed. It has worked well since then.

Now, the starter spins, put will not kick the gear up all the way to engage. I seem to remember reading not to use any lube on the gear drive.

What will be the best thing to clean and lube the drive, or should I just replace the drive. If I should replace, anybody know the pt # for the drive?

It is a Briggs, 6.75 Intek. The model of the engine is a 120602-0119-E1-06033-FA, and it is a 695550 starter.

Thanks