Theory of two stroke electrical ???

[simso]

Hey guys, trying to troubleshoot electrics on my back up engine its and old 2 stroke mercury 20hp. I understand 4 strokes but the electric side of 2 strokes is a bit lacking and then the next part how does one test each compenent of the system. Any help would be appreciated
Thanks Steve

[marshmat]

By electrics, are you referring to the ignition system or the ancilliary power system?
If you're referring to the ignition, your motor could have conventional points, or a CDI (capacitive-discharge ignition) computer. The power comes from a coil buried under and within the main flywheel. Points gradually wear out and can be replaced for about $10 when they do. CDI is supposed to last forever with no deterioration; if it does fail, its preferred way to go is the complete and utter failure of the whole damn thing at once, which costs well into the 3 figures to fix even if you do it yourself.
The ancilliary electrics, if you have any, usually tap off another coil in the flywheel. This one is arranged in similar fashion to an alternator, and its output runs through a rectifier before coming out the battery cables.
Let us know some more details of what's broken and we'll try to steer you in the right direction.

[simso]

Yeh sorry about that, you were correct in your assumption of the ignition electrics. It has a pick up for two sensors under the flywheel, these go to a rectangular box which then feeds out two wires which go to two coils and then feed on to the plugs. On the outside cowling of the engine on the front clip of panel it also saids thunderbolt ignition. Im a jet engine mechanic by trade, but I deal with turbines and 4 strokes, this is the first two stroke Ive ever actually worked on. Gonna chase up a maintenace manual today. Just dont really know where to start. Any help is appreciated
Thanks Steve