Small Engines (Lawn Mowers, etc.): Top Dead Center, power stroke, shear pin

Question
QUESTION: How do i locate top dead center on a flywheel with the spark plug out??? This would be typically on a 5.0 briggs engine that has a spun keyway and a violent kick back( almost a break tyour arm pull back) Someone had this beautiful engine and spot welded the nut to the shaft instead of replacing the shear pin what stupidity aye?? well anyhow i am going to attempt slicing off the nut with my trusty wiz wheel and check the shaft and flywheel. any good tips before I encounter this job? Thanks( its on a Power Pro self Propelled Mower. Thank you John

ANSWER: Hello John:

If you are Replacing the Flywheel Key, then TDC Does Not Matter in this Case. The Flywheel Key Times the Firing of the Plug to the Position of the Piston During the Power Stroke. TDC is Used when Setting the Valves and Setting the Gap on the Old Style Point Set Engines. Once the Flywheel Key has Been Replaced, then the Timing for the Plug Firing will be Correct and the Violent Kick Back should be Corrected Also. Please, Do Not Hesitate, If you Hit a Snag or this Does Not Correct the Problem, I am Here if You Require More Assistance. Hope this Helps. Let me Know What Happens, Please. May the All Mighty Bless You and Yours. 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 8pm EST (US). My New Day Starts then. Comments and Ratings are Greatly Appreciated. Thanks.

Respectfully

John

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

QUESTION: THANK YOU JOHN... THAT ALL MAKES PERFECT SENSE, WHILE CHECKING THE BRIGGS ENGINES SHAFT TO SEE IF IT WAS BENT I TURNED HER ON HER SIDE AND SUPPORTED IT WITH A STAND, PULLED THE PLUG WIRE OFF SO SHE WOULD NOT FREAKISHLY START FROM TURNING THE BLADE...AND ON A 1/2 REV. OF THE BLADE I USED MY THUMB AS A MEASURING GAUGE  IN RELATION TO THE BLADES EDGE TO THE INSIDE OF THE MOWERS INTERIOR CUTTING CIRCUMFERENCE, SAME DISTANCE DOING IT TWICE. IS THAT ACCEPTABLE FOR A QUICK CHECK?
PS..SORRY FOR THE CAPS, REGARDS, JOHN

Answer
Hello Again John:

No Worries about the Caps. It Happens. I Usually Suggest you Remove the Spark Plug and Turn the Engine Using the Starter. I Use White Paint to Mark the Center Bolt to Make it Easier to See. Watch the Center Blade Bolt. If the Blade Bolt Turns True, then the Crankshaft is Straight. The Crankshaft can have a Slight Wobble. The More the Center Blade Bolt Wobbles the Worse the Crankshaft is Bent. Using the Deck as a Guide is Not Suggested Due to the Deck Not being True. Some Engines get Mounted Slightly Off Center at Times and this Makes the Crankshaft Appear to be Bent when it Actually is Not. Always Tilt a Small Engine so the Spark Plug is Up. This way the Crankcase Oil Does Not Enter the Crankcase Breather and If Tilted for a Long Period, the Crankcase Oil Does Not Seep by the Rings and Flood the Compression Chamber. Please, Do Not Hesitate, If you Hit a Snag or this Does Not Correct the Problem, I am Here if You Require More Assistance. Hope this Helps. Let me Know What Happens, Please. May the All Mighty Bless You and Yours. 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 8pm EST (US). My New Day Starts then. Comments and Ratings are Greatly Appreciated. Thanks.

Respectfully

John