I have a Poulan rideing mower model number pb1842lt that I bought a jumper wire was in the 20amp fuse I put a fuse in and still have no fire ?

SOURCE: Poulan Riding Mower won't crank, battery OK.

Forget the safety switches for now.The first thing I would check would be the fuse. It will be located on the battery side of the solenoid. Follow your positive battery cable to the solenoid. There will be a small red wire coming off of that post with an inline fuse. If the fuse is good, check your solenoid. There are two wires plugged into spade terminals at the bottom of the solenoid. Unplug the one that is insulated, the other one is a ground. Hook a test light from that wire to ground. When you turn the key to start (with the brake pedal held down), it should light. If it lights, your solenoid is bad. If not, then you can start looking at switches. Probably will be one of the two. Hope this helps. Dwain

SOURCE: My riding mower blows fuses once you turn the key.

Sounds like you are on the right path, maybe some wires on the ignition were replaced backward, and you are sending +12v directly to ground? Does it blow right away?

SOURCE: Poulan Riding Mower will run in neutral, not in forward or revers

you have safty switch on the mower one or more are bad there are three of them
win you put in reverse some mower will cut off this is a safty device on some mower

SOURCE: POULAN 42" 19HP RIDING LAWN MOWER

42 inch poulan belt broke on mower deck diagram to replace new belt

SOURCE: my westwood ride on mower, model 2012 wont start.

Could be a few things, First, you say it's getting fuel, but is the fuel fresh? It may have water in it and act like your engine. Did this problem just start happening? Did you happen to ride over something that may have sheared the key on the flywheel? This would throw the timing off on the engine. If you can try to start it while spraying gas into the carb throat and it keeps running, then it could just be a dirty caburetor or a misadjusted carb float. Good luck, Bill