QuestionThanks once again. Just can't locate the clutch safety switch. Any thoughts where it is located.
And, when using a jump wire, I'm just inserting a wire into both ends of the connector with the switch removed -- correct?
And would a bad ground be contributing to the problem as well?
>>>
Below the thread from our discussion as a reminder of where we are:
I have a Briggs 12Hp engine (model 28407; type 1026-E1; code 980205ZA) on a Sears Craftsman Lawn Tractor (Model 917254520) and I don't have a spark to the spark plug. I've replaced the solenoid, the starter and the battery has a full charge. When I turn the ignition key, the engine's flywheel just spins and spins. When I have turned the engine over, I've held the wire close to the tip of the plug and I see no spark (nor feel anything through the insulation).
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 Shut Off Wire at the Control Bracket First, Check for Fire at the Plug. If Still No Fire at the Plug; Then Disconnect the Shut Off Wire at the Coil (usually requires removal of the blower housing) 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. On Some Model JD Engines, there is a Igniter that Goes Bad and Not the Coil. The Igniter is the Same as an Ignition Module on Other Models. 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 an Indication of a Bad Coil/Ign 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. Hope this Helps. I am Here if You Require More Assistance. Let me Know What Happens, Please. Thanks.
Good Luck
Respectfully
John
Update: I disconnected the black wire (shut off wire) that goes to the magnetron in front of the flywheel and here what happens: I am getting spark to the spark plug wire but not to the plug. But, when I wrap a wire around the base of the spark plug and ground it, I then get a spark to the plug (nice blue spark at the gap). Previously, when the black wire was connected to the magnetron, nothing. What's the problem?
You mentioned the seat and blade switch which I've located but not the clutch switch. I have jumped-wired the seat switch but not the clutch or blade switch. Same result as above. When I move the lever to engage the mower absolutely nothing happens when I turn the ignition (as it should but I'm not ruling that switch out unless it's already out of the picture with the black wire disconnected at the magnetron).
Also what is the gap between the magnetron and the flywheel? Right now I have it eyballed away enough to clear without rubbing. Could an inaccurate gap be the culprit? I noticed that there are two wires (black and red) that go underneath the flywheel to a diode I believe, fyi. Are those wires to the alternator?
I doubt it but I currently but do not have the deck pulleys connected if that is interfering with anything....?
I've gone to the Sears web site and to their drawing of this model lawn tractor which is useless -- nothing really identified. But I have the owner's manual with the parts and a schematic which is much easier to read.
Many thanks and thanks for sticking with me on this...!
>>>
Then you said to check all the switches and if the problem still exists,it's a short in the harness.
Hi Bill:
OK. If the Starter Does Not Turn the Engine with the Spark Plug Removed and you can Turn the Engine By Hand, then Do the Following Checks to Determine if the Stater ot the Solenoid is the Problem. Use your Jumper Cable Set and Attach the Positive Lead Onto the Positive Post of the Battery (make sure the Battery is Fully Charged or is a New Battery). Now Firmly Touch the Large Post on the Starter. If the Starter Does Not Turn, then the Starter is Bad. If the Starter Turns the Engine Properly, Then Check the Solenoid. Firmly Touch the Small Post at the Base of the Solenoid that has the Ign Wire Attached to it. If The Starter Does Not Turn and the Solenoid Clicks, Then the Solenoid is Bad. From Your Description it Sounds like the Starter needs Replacing. I Do Not Suggest a Rebuild. Usually the Problem is More than Bushings and Brushes when a Starter Gives Problems like this. Hope this Helps. I am Here if You Require More Assistance. Let me Know What Happens, Please. Thanks.
Good Luck
Respectfully
John
AnswerHi Again William (Bill):
A Bad Ground will Not Cause the Problem with the Safety Switches Grounding the Coil/Magneto/Ign Module. The Clutch Safety is Located Inside the Instrument Panel Under the Battery Holder on the Left Side of the Mower if you were Sitting on it. You are Correct on the Jumper Process; Just Remember that on Some Mower you Just Unplug the Switch and on Others you Jumper the Harness. You are Correct; if the Mower Requires Jumpers for the Harness, then Just Push the Wire Ends Into the Harness and you Bypass the Switch for Testing. I Used Blade Type Stacons and Made Jumpers so I was Sure to Get a Good Connection in the Harness Connections. 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
