No spark on B&S 285707 1996

[Dave Olley]

I bought this engine to replace a broken engine on my Stiga mower.
It's on and all connected up and it turns over well, but no spark. The wiring is supect as the wiring loom on the engine did not match the wiring loom on the newer tractor, so I just matched up wire colours and joined them together. This left one wire protruding from the engine, with nothing to attach it to. I checked and this wire comes from the bottom of the coil and I have seen it described as the kill wire and the earth/ground wire. The coil connection is good, but what should the other end be connected to.
Excuse the terms I use which may not be correct. I am an English man living in France and I have found this forum to be the best for getting advice. Thanks, Dave

 

[Bertrrr]

Your ignition key switch needs 12 volts for the Run position / 12 volts for start , the wiring is not right for sure a wire coming from under the flywheel cover should be your ignition source,
the coil generates the spark , to the plug start at that wire and see if it's got anything if not work backward from that point

 

[Dave Olley]

Sorry, the wire is from the underneath of the coil. The wire from under the flywheel cover is connected properly and the starter motor turns the engine over correctly
Thanks

 

[Forest#2]

The wire from the bottom of the coil is used to kill the engine by stopping the spark when IT'S GROUNDED. If the engine happens to start you will have to ground this wire to kill the engine. It will bite you if you just grab onto it with the engine running.
If on a riding mower it normally connect to the M terminal wire on the ignition switch.
If you happen to apply 12v to this kill wire the magneto will be friend immediately and then no spark.

If the wire is just hanging loose and not grounded you should have spark as the engine cranks if the coil is gapped at .010-.012 air space to the flywheel magnet. If no spark and these condition met you have a bad magneto. If a Briggs engine just use a clone $15 magneto. No need in the OEM $80 one.

What is the Model, type and code of your engine? I see it's a 28 series Briggs, but the complete model, type and code needs to be posted so as to get precise logical answers to questions
Is this a riding mower?

When asking questions about engine you should always post up ALL the ID information??????????????????
AND maodel number and serial number of the machine if wanting to know about the wiring harness, ignition switch etc