Murray 30" MER no spark

[L0n3s0m3_M0w3r]

I have taken pretty good care of this mower, sharpening the blade, replacing the air and fuel filters and spark plug and oil seasonally. A couple of years ago I did what I think in the automotive world is referred to as a frame off restoration, removing everything, cleaning and degreasing surfaces and replacing all the pins, bolts, washers etc. and belts with new. Over the years I've replaced other parts as required, batteries, safety switches, belts and ignition. This model has a Briggs & Stratton 28000 series 10HP single cylinder, L-head engine.
Recently upon attempting to start it, it cranked fine, started briefly, sputtered and that was it. All subsequent attempts to start it have failed. I've replaced the coil, ignition switch, bypassed all safety switches with paperclips but still there is no spark. You can literally hold the sparkplug wire in your hand while cranking. I've checked the diode with a meter and it reads differently forward and backwards and that's about all I know about that. So before blindly replacing all the safety switches I thought of seeking advice and here I am. Any suggestions are greatly appreciated. I haven't been able to mow in weeks and there are no kids who come around and offer.

Edit to add:
Murray model: 309029x92B
Briggs & Stratton model: 28R707, Type: 1120E1, Code: 030430ZD

Also replaced the wiring harness a couple of years ago.

 

[Scrubcadet10]

should be a black kill wire that plugs to the ignition coil as well, pull it off and try to start. if you have spark with that pulled of the kill wire is being shorted to ground.

 

[hdsport]

From briggs forum.

The plug that runs to the carb bowl is the "Anti After fire valve" to prevent fuel from bring drawn into the cylinder after the key has been shutoff.
Most likely you have no spark because voltage got to the ignition coil and fried it, OR insulation was melted off the coil kill wire and it is now shorted to ground and causing the coil to not produce spark. Quick way to check is to unplug the kill wire from the coil and see if you've got spark. If you do with the wire unplugged the wire is shorted to ground or a key switch issue.
If you unplug the wire and still no spark , the coil is dead. BUT before you buy a new coil and put it on, you need to check to be sure there is no voltage on that kill wire. Any amount will fry the new coil.
The two sides that come from under neath the housing are most likely wires coming from the Stator (alternator).

More from forum.

Unplug the 1 wire that is going to the coil. Try to start. If it has spark with that wire unplugged. It is either shorted to ground or there is a problem with the key switch.

 

[hdsport]

I had the same "no spark" issue and found that I crushed the black wire behind the starter when I did a starter pinion repair and then reinstalled the starter.

 

[L0n3s0m3_M0w3r]

should be a black kill wire that plugs to the ignition coil as well, pull it off and try to start. if you have spark with that pulled of the kill wire is being shorted to ground.

Thanks, I'll try that but the black wire of which you speak is in plain sight and free of any kinks or pinches. I had to remove it and reattach it when I replaced the coil. But what the heck. Couldn't hurt. At this point I'd stand on one foot and sing Help me Rhonda.

 

[L0n3s0m3_M0w3r]

From briggs forum.

The plug that runs to the carb bowl is the "Anti After fire valve" to prevent fuel from bring drawn into the cylinder after the key has been shutoff.
Most likely you have no spark because voltage got to the ignition coil and fried it, OR insulation was melted off the coil kill wire and it is now shorted to ground and causing the coil to not produce spark. Quick way to check is to unplug the kill wire from the coil and see if you've got spark. If you do with the wire unplugged the wire is shorted to ground or a key switch issue.
If you unplug the wire and still no spark , the coil is dead. BUT before you buy a new coil and put it on, you need to check to be sure there is no voltage on that kill wire. Any amount will fry the new coil.
The two sides that come from under neath the housing are most likely wires coming from the Stator (alternator).

More from forum.

Unplug the 1 wire that is going to the coil. Try to start. If it has spark with that wire unplugged. It is either shorted to ground or there is a problem with the key switch.

Thank you. I was unaware of a plug running to the carb bowl. I'll have a look. I replaced the key switch last week. Even though there is no visible damage to the black kill wire, unplugging it may lead to something else. Trial and error right?

 

[L0n3s0m3_M0w3r]

should be a black kill wire that plugs to the ignition coil as well, pull it off and try to start. if you have spark with that pulled of the kill wire is being shorted to ground.

Disconnected the black kill wire but still no spark. With the blower housing removed the wire is in plain sight and completely free of any obstructions or crimps. Disconnected from the coil I'm able to pull it out with ease.

 

[L0n3s0m3_M0w3r]

Thank you. I was unaware of a plug running to the carb bowl. I'll have a look. I replaced the key switch last week. Even though there is no visible damage to the black kill wire, unplugging it may lead to something else. Trial and error right?

I had a look and there is nothing connecting to the fuel bowl.

 

[L0n3s0m3_M0w3r]

Seems to have plenty of compression with good pressure at the spark plug hole. Guess I'll replace all safety switches again. Will take a few days as I'll have to order them since my truck is broke down as well.

 

[Scrubcadet10]

No spark with the wire unplugged is a bad ignition coil...
What did you set the air gap at?>