Small Engines (Lawn Mowers, etc.): Poulan lawn tractor wont stay on, jumper cables, jumper wire

Question
I have a 3 year old Poulan riding mower.  We have put in a new battery, cleaned spark plug, replaced clutch switch, selenoid, and ignition switch.  Problem- when we jump start the mower it cranks right up.  As soon as we take the jumper cables off it dies and won't start.  The battery is fully charged.  Help my grass looks like a jungle.  

Answer
Hi Denise,

Go through my no cranking proceedure below.

Let me know how you make out.
Michael

I would check the starter first.  Jump the positive battery terminal to the starter and it should crank over.  If not, jump from a battery that you know is good, from a car.  If still nothing, the starter is bad.  If good, then you will need to trace the entire circuit from the starter to the battery.   The solenoid, switches the battery power to the starter, when power from the key switch is sent to the small terminal on the solenoid. To test the solenoid, first make sure that you have power at its large terminal which comes from the battery. Then jump power from that terminal or the battery positive post, to its small terminal. You should hear a click and the other large terminal that feeds the starter should be energized. If not, then the solenoid is bad. If good, then continue tracing the power through the key switch to the battery until you find the break in the power path.   All testing can be done with a 12 volt light or a voltmeter.  Most equipment has safety switches in  the seat and on the blade engagement lever. Check them by temporarily bypassing with a small jumper wire.