Small Engines (Lawn Mowers, etc.): Lawn Tractor wont start, briggs and stratton, starter shaft

Question
QUESTION: My tractor has a B&S model number 289707 12.5 HP engine.  After mowing my lawn I shut off my mower.  When I went to restart it about 15 mins later it would not start.  Before this it always started with no problems.  

When I turn the key, the starter spins.  I removed the dust cover and I can see and hear the gear spinning, however it does not engage the large gear ring.  Also, the battery was replaced this past fall.  

Any advice would be appreciated.  

Thanks in advance.  

Brian

ANSWER: Hello Brian:

From your Description, it Sounds like the Starter Drive Gear is Sticking or Stripped. Spray the Starter Drive Gear and Shaft with Lubrication. There May be Dust and Dirt Causing the Starter Gear to Stick and Not Travel Up the Starter Shaft. You can View a Breakdown/IPL of this Engine at this Site Addy, http://www.outdoordistributors.com/ and Select the B. Then Select Briggs and Stratton. Then Select Don't have Part Numbers. Then Select the File # 28. Then Select the Folder # 289700. This is the Breakdown/IPL I am Using for a Reference. You can View a Breakdown of the Starter on Page 9 of 17. Check the Inside of the Starter Drive Gear and the Starter Drive Shaft. If the Grooves are Damaged on the Starter Drive Shaft, then Replace the Starter. If the Grooves are Damaged on the Inside of the Starter Drive Gear, then Replace the Gear. Hope this Helps. I am here if you Require more Assistance. Let me know what Happens, Please. Thanks.

Good Luck

Respectfully

John

---------- FOLLOW-UP ----------

QUESTION: Update:
John, thanks very much for your reply, it was very helpful.  As I investigated further I noticed the large gear ring has some chunks taken out of it.  I had to remove the housing to get full look at it to find the problem.  The starter and its gear seem to be fine.  Once I advanced the gear ring manually I was then able to start the mower - woo hoo!  Your reply helped me find the problem.

I see the gear ring is #726 on page 6 of the doc your referenced.   The one on my mower is plastic; and apparently looks like some teeth have been missing for a while.  The replacement part (p.17) has the description of "Aluminum - service plastic ring gear only".  Does this mean the replacement is aluminum vs. plastic?  Also, is this pretty easy to replace?  Anything else I should know about fixing this?

Thanks again for your help,

Brian

Answer
Hello Again Brian:

Yes. All the Plastic Ring Gears I have Replaced have been with Aluminum Ring Gears and I Purchased them from the Site Addy I gave you. Even if you Can Not Replace the Ring Gear; it is Still Cheaper for you to Purchase the Ring Gear and Have it Replaced. To Me it is a Simple Procedure to Replace the Ring Gear. I Suggest you Remove the Flywheel and then Take the Flywheel and New Ring Gear to a Small Engine Service Center and have them Replace it for you. All you Should have to Pay is a Labor Charge. I Get $30.00 to Replace the Gear if the Customer has the Parts. To Remove the Flywheel; Remove the Blower Housing (metal engine cover). Remove the Flywheel Nut or Starter Cup (Depends on the Model). Now Attach a Steering Wheel Puller to the Flywheel Using the Threaded Holes in the Flywheel. Tighten the Puller. Now Hit the Puller with a Hammer. Repeat this Procedure Until the Flywheel Pops Up or can be Lifted Off the Crankshaft. Hope this Helps. I am here if you Require more Assistance. Let me know what Happens, Please. Thanks.

Good Luck

Respectfully

John