jgun45879 186 #1 Posted September 21, 2008 Hello, I am currently working on a friends 1982 GT-1848 tractor that would not turn over or run for the past two years. The wiring was butchered and someone had installed the battery backwards (polarity reversed). I aquired a wiring diagram and straightened out the wiring mess. This unit has an 18hp Briggs Twin engine. I have power going into the two prong plug going into the engine but no spark at plugs. I primarily deal with Kohlers so this Briggs is not something I know much about.Where do the wires on the two prong plug go? Rectifier or Magneto? How do I check them?Could having the battery in backwards and trying to start it burned something up? I need help from someone knowledgable with this motor please. Thanks, Jim. Share this post Link to post Share on other sites
TT-(Moderator) 1,131 #2 Posted September 21, 2008 The opposed twin Briggs on your 1848 features a dual-circuit alternator mounted under the flywheel. One lead is for the recharging of the battery and the other is for the lighting power. That is the 2 prong plug coming from the engine and it has nothing to do with the ignition system. The Magnetron ignition system is self contained and is mounted outside of the flywheel. It is virtually identical to a newer Briggs push mower ignition system with the exception of having two spark plugs leads. The single small black wire coming from the Magnetron coil grounds the circuit when the ignition switch is in the off position. If you unplug the wire from the terminal on the coil and turn the engine over, you should have spark. If that works, either the wire is shorted between the coil and the switch, or the switch is bad. If you still don't have spark, check the air gap between the coil armature and the flywheel (.010" - .014") and also make sure there is no rust accumulation on any of the armature "posts". If that doesn't "fix" it, the coil is bad and will need replaced. Share this post Link to post Share on other sites
