QuestionI have a Craftsman 37cc backpack blower model #636796912.
Worked perfect for a couple years. Now it runs perfect for about 15/20 min then sputters out. It will restart and run only for 20 to 30 seconds and die. Fresh fuel and perfect mixture. Ran with cap off, no change. Coil does not seem to be hot. HELP???
AnswerHello Randy:
>>Does the Spark Plug Fire when this Happens?
>>The Following is a Basic Instruction File I Made for Checking the Coil/Ign Coil/Magnetron/Armature on Small Engines. Any Input is Appreciated.
>>If the Unit Runs and Quits after 5 Minutes to 3/4 Hrs and will Restart after the Unit Cools (sometimes as little as 30min), then
>>Check for Spark as Soon as the Engine Quits.
>>Have a Good Plug with a Wire Around it Ready and when the Unit Quits Running, Remove the Plug Wire and Attach it to the Standby Plug. Check for Fire.
>> ***Be Careful, The Engine and Plug are Hot and I Suggest you Wear Gloves.***
>>If the Plug is Firing , then
>>Remove the Spark Plug from the Engine and USE IT to Check for Fire.
>>Sometimes a Spark Plug can have a Problem with Not Firing when Hot.
>>**To Check the Ign Coil if the Engine is Not Starting and Running at All; Remove the Spark Plug/s.
>>With a Good Plug, Wrap a Wire Around the Threads of the Plug and Attach the Other End of the Wire to the Engine Block.
>>Check for Fire at the Plug. If No Fire, then
>>Remove the Blower Housing (metal engine cover).
>>The Wire that is Connected to the Coil/Ign Module from the Shut Off Switch needs to be Removed (unplugged) from the Coil/Ign Module.
>>Now Check for Spark at the Plug.
>>If Spark, then the Shut Off Switch or the Wire is Bad.
>>If Still No Spark, then the Coil/Ign Module is Bad. If there are Safety Switches on this Unit and the Coil is Good; you Need to Check the Safety Switches for Being Bad and Check the Oil Guard Switch also.**
>>Does the Engine Turn Over like it Does when Cold Starting or is it Turning Easier/Harder?
>>The Following is a Basic Instruction File for Doing a Diagnostic on the Engine for this Problem. Any Input is Appreciated.
>>**Remove the Muffler and Make Sure the Exhaust Port is Clear.
>>If it is, then Try to Start the engine with the Muffler Off.
>>If it Starts and Runs Properly, then Clean the Spark Arrestor Screen in the Muffler or Replace the Muffler if Required. Some Mufflers will Split apart for Cleaning of the Screen and Some are Screwed/Bolted to the Outside and on Others the Muffler has to be Replaced.
>>If you Hit a Snag or this Does Not Correct the Problem, I Hope to be Here if You Require More Assistance. Hope this Helps. Let me Know What Happens, Please. May the All Mighty Bless You and Yours. Be Safe and Happy. Thanks.
Good Luck
Respectfully
John
PS: I am Allowed to Answer 3 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. All Follow up Questions are Accepted at Any Time. Comments and Ratings are Greatly Appreciated. Thanks.
Respectfully
John
