Gear-Pinion on starter worn out

I have a Craftsman 17 hp, 42" mower electric start 6 speed transaxle lawn tractor(model 917.271653). I recently had issues starting it. After troubleshooting my electrical system I pulled off the starter and noticed the Gear-Pinion (693713) was worn down to practically nothing. I was wondering if it would be an issue just to replace that part or do I have to replace the whole starter? I also noticed the new part I was going to order was a steel gear as opposed to the hard plastic which was on my old starter. Is there a difference? I'm following the specs from my owners manual and it gives me the part # for a steel Gear-Pinion.
And oh ya.......I thought I read somewhere that it requires a special tool to change this part. Any help would be greatly appriciated.

 

If the gear is worn down, it is a problem. If the number is for a steel gear and yours is a nylon gear, then that may be the problem. The steel gear has a different tooth pattern and doesn't match the flywheel that is made for the nylon gear. Did you buy this mower used, or did it come new with the nylon gear?

 

I bought it new but did have a local small engine mechanic work on it about 3 years ago and I'm pretty sure he replaced the starter.

 

I would bet your motor uses the plastic gear, they do wear overtime, I do not think I have ever saw a steel gear drive on a sears lawntractor.

 

the couple 31 series 17hp briggs I've seen have had the steel gear on the starter
check your flywheel gear section with a magnetic and see if it's aluminum or steel

The ipl I have for 31 17hp says
693713 for steel ring gear
695708 for aluminum or plastic ring gear

 

I tried the magnet to the flywheel and the magnet stuck to it.. I also referenced the B & S Engine model # 310707 type 0137-E1. And the craftsman part # for the starter itself 693551 and both reference the steel ring starter. The part # for the gear pinion itself on the starter is 963713 in the owners manual. I found a starter on amazon for $30.78 for part # 693551. It has a steel gear I think i'm going to go that route. Any ideas?

 

You can change just the gear with a small flat head screwdriver and a small 3/8" socket if you want.

 

Replaced the starter with a $38 starter from amazon with steel gears, started first try...Thank you all.