For small engine mechanics

Want to post pic of a part on a B&S twin cly mower engine. Mower died and has no spark. Should there be current on both wires of this part? It has curren t to one wire. What is
this called? Resister? Thanks in advance for your replies.

Congratulations, you've found the rectifier/voltage regulator which rectifies AC from the alternator stator and controls battery charging, but doesn't have ANYTHING to do with it not running!. Part # stamped on it, 491546, positively identifies it as such.

Engine makes it's own power for spark, at each coil/ignition unit, NO battery power is needed.

There's two electronic ignition coils connected in common through diodes to the "kill" wire or terminal on the engine. (second wire leaving the engine, besides wire from the regulator). The key switch/and/or safety switches ground this to chassis ground to stop the engine or prevent it from starting.

Disconnect that second wire and the ignition system of the engine is on it's own and spark should return.

Just remember, if it starts with that wire disconnected, the key switch won't shut it off!

If it DOES spark with the "kill" wire disconnected you can then trace the wiring in the machine and see what's shorted or what safety switch is shorting the "kill"wire to ground.

If spark does NOT return, you'll have to look under the flywheel shrouding to see if anything has happened to that wiring harness connecting the coils, as it's pretty unlikely BOTH coils have failed.

Most small engines have mag type ignition systems as Bob says and you need to find the mag wire and make sure it is not grounded out. I have a job today where I can make it run but I cannot make it run and also kick in the PTO so I will be pulling the mag ground wire and see if I can make it run and have the PTO kick in and if I can do that I will be installing a kill switch so the person can cut there grass which will go around all the safety switches. And before any body says anything about going around the safety switches this thing has be rewired by mouse and to fix it correctly would take a lot of time and a whole lot of $$$

Thanks for replies, will try to get it running and post back.

Just got back form trying to figure out this JD LA145 and instead of ti getting better it got worse. Now days they are over wiring these things and when something goes wrong it is big hair pulling mess