Small Engines (Lawn Mowers, etc.): rider with B&S 287707 engine wont start, jumper wire, loose wires


Question
Hi,

our riding mower is near the end of its life, and I'm trying to eke another season or two out of it before investing in a new one.

We had a problem with it starting before, and a repairman (who's no longer around) "rigged" it such that to start the engine, I have to sort of hot wire it.  He installed a "jumper" wire from the coil extending toward the negative terminal on the battery.  To start the mower, I would turn the ignition, step on the brake and touch the jumper wire to the terminal.  The mower has started just fine this way for 3 years now.  Even thought it's a redneck fix, I kind of am tickled by the ingenuity so I left it this way.

last weekend I went to start the engine and there was absolutely no spark when I touched the jumper wire to the negative terminal.  None.

Thinking the batter was simply dead from the winter (which happens about every other year), I tried to jump start it with a car (which always works fine).  But it still wouldn't even try to turn over.  No spark, nothing.  

Took the battery to a parts store and they said the battery is strong.  

What could be the problem? A bad coil?  I cannot find any loose wires, harnesses or blown in-line fuses.

this mower is really at the end of its life, so taking it to a repair shop is probably not an answer since they'll certainly want to "correct" the jumper wire starting system, and THEN fix the new problem.

Any thoughts?

Thanks for your help!

Answer
I'm not sure what you're referring to by a jumper wire from the coil that will allow the engine to fire.  The tab on the coil is for the kill wire.  It kills the spark by grounding the coil.  So if the wire is hooked to that tab, then by touching it to ground, the coil will not fire.  If you put power to that tab on the coil, then you will probably ruin the coil.  Could the wire go to the solenoid?

Let me ask this.  When you turn the key to the start position, does the starter turn over?