This is a C34284 OEM starter used on Briggs and Stratton Vanguard Equipped Tractors. 3012, 3014, 3016, 3018, 4016, 4018 and others. This is the starter you need IF YOUR HAS A "PLASTIC" starter gear and an alluminum ring gear.  This is the wrong starter if you have steel gears. 
 
We do offer the steel gear starters OEM CLICK HERE , and an aftermarket replacement starter for this model here too.
 
We highly recommend replacing your key switch and solenoid at the same time to protect your new starter and to make sure your starting issues are fixed by replacing all the major componets of your starting system. We offer the options to do so at check out and have info on these products on our store pages.