Hmm, hard to say. By the way, any ground problem you found involving the electrical system has nothing to do with the ignition on this engine.

I would disconnect the "Kill" wire AT the coil and see what happens. You will need some other way to stop the engine then, cut off gas, pull plug wires. I would also be sure the mounting surfaces on the block and on the coil were bright. That is important, cleaning the magnet and coil laminates is not. There is a possibility of an intermittent short somewhere in the safety switch or kill wire system. (Check where the Kill wire goes under the cooling shroud)

IF I under stand you correctly, the starter turns the engine OK but there just isn't any spark?

Walt Conner

Walt, thanks for such a quick reply, wow.

I will double check the mounting surfaces, then try the pulling the "kill" wire.

Yes, the starter spins it over but no spark to either plug.

Sorry I haven't posted back. I have been busy with another project.

The kill wire is good, I have the engine covers off and have it isolated. As for the safety switch, any idea where I can get a diagram for the wiring so that I can get a decent understanding of all the safety swithches and other nuances of a garden tractor.

Thanks.

Doug

***"The KILL WIRE IS GOOD, I have the engine covers off and have it isolated."***
What exactly do you mean by that statement? Are you saying the kill wire is intact, securely connected to the coil?
If that is what you mean.....you have misunderstood what Walt was telling you to do. On these ignition systems, you CONNECT the kill wire to a grounded surface in order to kill the spark. The connection to ground is accomplished by CLOSING the contacts of a switch. Old fashioned engines typically only had a single switch (located on the throttle control assembly on the engine) to facilitate "killing the coil". Modern machines can have multiple switches at different locations that perform a "safety interlock" function (seat switch, brake/clutch switch, etc) to kill the engine when "forbidden actions" are attempted by the machine operator. What Walt was instructing you to do with the kill wire AT THE COIL was to UNPLUG the wire from the coil, and then check for spark. People sometimes think that you need to have a good connection of the kill wire (at the coil) in order for the engine to run. Just the opposite. The function of the kill wire is to KILL the spark by connecting the kill circuit TO A GROUND when you want to kill the engine spark. The reason you are asked to unplug the kill wire from the coil, AT THE COIL, is to determine if that kill wire is being connected to a ground somewhere, due to the wire insulation being chafed away (shorted to ground) or by a defective or mis-adjusted safety switch (switched to ground). If you had unplugged the kill wire from the coil, AT THE COIL, I would have expected your response to be, "Kill wire unplugged from coil there is still no spark." or "Kill wire unplugged from coil, good spark."
Just wanted to make sure you understood what you need to do there.

Mownie,

You're right I misundestood Walt's instructions. I will pull the wire off and check for spark.

"I would disconnect the "Kill" wire AT the coil "

"You're right I misundestood Walt's instructions"

??

Walt Conner

In my haste, I read it too fast. My apologies.

Last night I disconnected the kill wire at the coil. It started. My son drove it around for a few minute and took a few swipes mowing. Shut it down and it restarted. I thought we had it figured out.

We let it sit for about an hour to do some other things and went to start it to pull it back in the garage,... no start, no spark.

Any other suggestions?

Doug

Try to "trace" the kill wire from where it connects to the coil, to its next "connecting point". This may lead you to the throttle linkage area near the carburetor, or to a terminal on the ignition switch. It might "branch off" from either of those locations and continue to a seat switch or a clutch/brake pedal switch. The idea behind your search is to try and identify all the places where the "KILL WIRE" circuit travels to, and connects. Any single switch that is connected to the kill wire circuit is capable of "switching to ground" and thereby "killing the spark, and the engine. If you can identify all switches that can ground the kill wire, you then have to determine whether a specific switch is defective or simply out of adjustment. Click the link below and study the Briggs IPL for your engine. Go to page 8 of the IPL. First, find item # 222, this is the throttle cable attachment point and also incorporates the OEM Briggs "stop switch". Inspect this switch carefully to determine if it has lost the isulator components that could cause this switch to "short to ground". Find item # 356, 356A, and 356B. This is the OEM Briggs kill wire (stop wire). Notice that 356B is a "two wire" configuration. YOUR engine will only feature one of the 3 configurations of stop wire. 356B is an example of what I meant about the kill circuit "branching off" to other locations. Now, you will have to trace the circuitry to determine how many things (switches) are employed on your particular machine. Keep in mind, SOME seat switches (OPSS) have a "shorting plug" or connector that connects to the switch terminals. These "shorting connectors" cannot simply be "unplugged" from the switch to check or defeat. The shorting function of these connectors will deploy when the connector is removed from the switch and that will ground the kill circuit the same as if the seat was "vacant".

Here is a link that might be useful: 422707 link

IF there is no spark with the "kill" wire disconnected AT the coil, then the coil is certainly suspect. You did brighten, clean, the mounting areas of the coil and the engine block?

Walt Conner

"IF there is no spark with the "kill" wire disconnected AT the coil, then the coil is certainly suspect. You did brighten, clean, the mounting areas of the coil and the engine block?"

Yes, that is correct. The coil and head were the coil coil meet have been cleaned. And the kill wire is still disconnected at the coil.

Doug

***"The coil and head where the coil meet have been cleaned. And the kill wire is still disconnected at the coil."***
Replace the coil, if you have done the things suggested, and still get no spark, the coil is defective.

That's what I thought, but I wanted to make sure that there is nothing else that controls the coil. Especially since we replaced it when I first discovered there was no spark right after he got the tractor. I guess we got a bad one?

Have a great 4th!

And provided that everything you have done/said is accurate :^) Happy Independence Day everybody.

"Especially since we replaced it when I first discovered there was no spark right after he got the tractor. I guess we got a bad one?"

While that is a possibility, it is unusual. This is an expensive item that I would not be too anxious to replace repeatedly. You did get the coil on with the correct side up after cleaning surfaces? Have you stuck a Phillips screw driver in the spark plug lead, removed both spark plugs and spun the flywheel by hand past the firing point while holding the Phillips screw driver between thumb and finger while touching the cylinder head with another finger? This will give you a "feel" for what, if anything is going on with the coil.

Spin the flywheel briskly, if you have a strong urge to let go, coil is likely OK, if you just feel a tingle or nothing, bad news but you have to spin that flywheel briskly.

OR better yet, get your son to hold the screw driver. (grin)

Walt Conner

Yes, the coil is mounted right side up. What I actually did was pull the plugs and attached them to the spark plug leads and I held one plug to the head while my son held the other plug to it's respective head. I thought if it needs to fire them in the holes, it should be able to fire them outside the holes. (Yes, they are both new plugs. Although in our quest for answers we even tried the old plugs still nothing.) Do you think I should still try the screwdriver test?

Doug

"Do you think I should still try the screwdriver test?"

No, that is just something I do.

Walt Conner

OK, here's the fix.

It shouldn't be news to those that are following this that I was really getting frustrated. Things just didn't make sense, I was getting spark sometimes but not others.

Out of frustration rather than pulling one of the plugs (for the hundreth time) to check for spark after having it running a couple of minutes earlier, I grabbed one of the old spark plugs. And it was showing a nice blue arc. I checked the other cylinder, same thing. But it still wasn't starting. Confused I pulled the new plugs to check to see if they were sparking, and nothing. AH-HA. Installed the old plugs turned it over, and she fired right up and has ever since.

The new plugs were Champion EZ-start plugs that were cross referenced to the mower. I don't think I will be recommending these to anyone. Has anyone else had an issue with these plugs?

Thanks everyone for their time, patience, and advice.