QuestionQUESTION: Hello John,
I have a Craftsman mower Model No. 917.377610.(About 10 years old). The mower was running great when I carelessly was mowing around a large tree and the blade hit a large root, the engine immediately stopped. Since then I can't restart the engine. All I can get after many pulls of the starter cord is an occaisional sputter or small backfire. The blade or the shaft does not appear to be bent. Any ideas of what happened or what to look for?
Thanks for your great work,
Joe
ANSWER: Hello Joe:
The Flywheel Key is Damaged and Requires Replacing. Also, you Need to Check the Crankshaft and Make Sure it is Not Bent to the Point it will Cause Damage when you Get the Key Replaced and Start the Engine Again. The Following is the Instruction File I Made for Correcting this Problem. It is the Basics and if you have a Question, Please Ask. Any Input to Make this File Better is Appreciated. ***Remove the Spark Plug and Tilt the Mower so the Plug Hole is Facing Up. First Make Sure the Blade is Tight. Now Turn the Engine and Watch the Blade Bolt. If the Bolt Wobbles, then the Crankshaft is Bent and May be A Problem After the Key is Replaced. If the Wobble is Slight, then Replace the Key. If the Wobble is Severe, then the Engine is Shot and the Only Way to Save it is to Replace the Crankshaft. Usually this is More Expensive than Purchasing Another Mower. I Suggest you Price the Repair at a Local Small Engine Service Center and a New Mower. If you are Going to Replace the Crankshaft yourself, then I can Give you and Instruction File for that Also. Now 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. On Some Models you Can Not Use a Puller and Must Use a Pry Bar and a Pipe Cap that is Slightly Larger than the Crankshaft. Place the Pipe Cap Over the Crankshaft to Protect it. Place the Pry Bar Under the Thick Section of the Flywheel and Pull Up Against the Flywheel. **BE CAREFUL DO NOT PUT A HOLE IN THE BLOCK UNDER THE FLYWHEEL** Now Hit the Pipe Cap that is on the Crankshaft (covered with the Pipe Cap). Repeat the Procedure Until the Flywheel can be Lifted Off the Crankshaft. *** Now Replace the Key Between the Flywheel and Crankshaft and Reverse the Procedure. Be Sure you have the Flywheel Torqued to at Least 55 - 60 Foot Pounds. The Key Times the Plug Firing and is Not Designed to Hold the Flywheel from Turning on the Crankshaft. The Flywheel Nut or Starter Clutch Torque Does that. Once the Engine is Running and IF you have a Bad Vibration from the Engine, then the Slight Wobble is the Cause for this. I Suggest you Not Use the Mower and Either Replace the Crankshaft or Replace the Mower. According to the Breakdown for this Mower, the Engine is a Tecumseh Model 143.986706 (Sears) and the Flywheel Torque is as Stated Above. To View a Breakdown of this Unit Go to this Site Addy, http://www.searspartsdirect.com/partsdirect/index.action and Enter the Model Numbers (143.986706 for the Engine) and Click Search. From this Page you can View Diagrams and Parts Lists for you Equipment Using the "View Sub Components" Section. 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. Thanks.
Respectfully
John
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QUESTION: John,
You hit it right on the head with your answer on this one. I got the flywheel off and sure enough the flywheel key was mangled. One question, if you can, what should the gap be between the magneto coil pickups and the magnet on the flywheel?
Thanks again for your expertise.
Joe
ANSWER: Hi Again Joe:
The Coil is Gapped .020in from the Flywheel. You can Use a Cardboard Panel from a Drink Carton (I Use Mt Dew 24 Pk) and Make a Card that is 6" X 4" and Put it Between the Coil and Flywheel Magnets. Let the Magnets Pull the Coil to the Flywheel and then Lock the Coil in Place. Then Turn the Flywheel while Pulling on the Cardboard Panel to Remove the Panel. 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. Thanks.
Respectfully
John
---------- FOLLOW-UP ----------
QUESTION: Hi John,
Something's got me puzzeled with this mower. While I have it all apart, I thought I'd check to see if I have a good spark. I used an Ohmmeter and checked the ground wire that goes to the coil. The cable and mechanics that operate the brake and switch seem OK. With the Operator Present handle tied down,(as though I were running the mower) I get a ground to the coil. Seems backwards to me. Shouldn't the ground be supplied to the coil when the handle is released, to stop the engine?
I tried spinning the flywheel with a drill with the spark plug out and the Oper. Pres. handle tied down. I couldn't see any spark with the ground wire connected to the coil, but if I removed the ground wire I did have a spark????What am I missing here?
Thanks again,
Joe
AnswerHello Joe:
You are Correct. When the Engine Stop/Brake Cable is Pulled, it Pulls the Ground from the Coil Stop Wire and when Released, it Grounds the Stop Switch an this Grounds the Coil to Stop the Plug from Firing. Check the Brake/Shut Off Bracket that is Attached to the Engine. On it is a Small Stop Switch that Actually Grounds the Coil to Stop the Coil from Firing the Spark Plug. Make Sure the Stop Switch is Still Popped Into the Bracket Securely and that the Shut Off is Moving Away from the Blade Switch to Break the Ground Connection. 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. Thanks.
Respectfully
John
