Small Engines (Lawn Mowers, etc.): Craftsman Mower Starting Problem, briggs stratton engine, briggs stratton

Question
QUESTION: I have a Craftsman Riding Mower (Model No. 917.273634) with a Briggs & Stratton engine 18.5 hp (Model No. 31P777). Went to start it a few days ago and engine wouldn't move. I checked battery (it was dead) and plug (slightly fouled) so I changed both. Went to start it tonight. This time nothing would happen but then the flywheel would start spinning very fast but the spark plug did not seem to be firing. Any suggestions? I also checked oil and tried putting gas in carburetor to see if it would turn over but nothing happened.

Thanks in advance.

ANSWER: Hello Mike:

By Spinning Very Fast; Do you Mean Fast and Has Compression Stroke or Fast as though the Spark Plug is Not Installed? If the Engine is Turning Normal for Starting but the Plug has No Fire, then Remove the Spark Plug. Wrap a Wire Around the Threads and Attach the Other End of the Wire to the Engine Block Turn the Engine and See if the Plug Fires. If No, then Disconnect the Control Bracket Shut Off Wire First, Check for Fire at the Plug. If Still No Fire at the Plug; Then Disconnect the Shut Off Wire at the Coil and Check for Fire at the Plug. If No Fire at the Plug , then the Coil/Ign Module is Bad. The Coil/Ign Module to Flywheel Gap is .020in. If the Plug Fires at Anytime During these 2 Checks, then a Safety Switch or Wire May be the Problem. Yes the Engine will Turn Even with a Bad Safety Switch. The Blade Safety is Usually the Cause of this. The Starter Turns and The Engine Doesn,t Fire is and Indication of a Bad Coil/Ing Module or a Faulty Blade Safety Switch. The Clutch Safety Prevents the Starter from Engaging so the Mower Does Not Move when the Starter Turns the Engine. The Seat Safety is Designed to Stop the Engine if the Blades are Engaged or the Clutch Safety is Not Engaged when you Leave the Seat. If the Engine Turns Fast as If the Spark has Been Removed, then Check or Replace the Flywheel Key. To Check or Replace the Flywheel Key; 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. Replace the Key if Any Damage is Observed in the Key. In your Case it May have Sheared. Just a Thought; Is the Crankcase Oil Overfilled and Have a Gas Smell to it? Hope this Helps. I am Here if You Require More Assistance. Let me Know What Happens, Please. Thanks.

Good Luck

Respectfully

John

PS: I am Allowed to Answer 10 Questions a Day. If you See I am Maxxed Out, then Try Submitting your Question at or Just After 9pm EST (US). My New Day Starts then. Thanks.

Respectfully

John

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

QUESTION: By spinning fast, there is no fire from the plug. It just spins very fast. I did check the plug and there was fire.

How would I check the seat safety switch to see if that is the issue? I was thinking flywheel key too and will check that.

Finally where would I find the blade safety switch?

Answer
Hello Again Mike:

If you have Fire at the Plug and the Engine is Turning Very Fast, then I Suggest the First thing to Check is the Flywheel Key. If the Flywheel Key is Good, then the Next thing is to Check the Cylinder Compression. Hope this Helps. I am Here if You Require More Assistance. Let me Know What Happens, Please. Thanks.

Good Luck

Respectfully

John