Briggs & stratton 15hp. Wondering if starter is bad???

I have a white riding lawn mower with a 15 hp briggs & stratton engine. Sorry I don't have specs on engine right now but can get tomorrow. I got the mower running and drove it about 10 feet then it died. Would not turn over very well after that. I noticed that the gear on top of the starter was engaged up and into the flywheel. My question is wouldn't this gear go back down either after starting the mower or after turning it off?? I manually lowered it down and moved it around to a different position and depending on how I turn it I can get the engine to either 1. do nothing or barely start to turn or 2. turn over but not fire, however only will turn a couple times. I am assuming the starter may be bad. Am I correct in this assumption or should I look for another cause?? Thank you.