Ive got a small, very old briggs and straton engine that i cannot seem to get to spark. it is 1 cylinder. the breaker points make a clean contact and everything. it has a starter motor in the circuit which runs off a 12 volt dc supply.

I am not exactly sure where to start i dont know the order all of the electrical components are in. I asume the magneto ring is the origin of current, passing through the red wire and the current must go back into it through being earthed by the black wire right? i still need to find a way to get the battery and starter motor, and condensor and regulator? into the circuit, can somebody tell me what order these should be in and in paralell or series etc.

the keyswitch will be bypassed in this circuit also cuz i think its screwed... ill put a new one in if neccessary though.

my basic problem is i dont know which way current flows, where it flows, and how it gets back so any help on this would be good.
Any feedback would be greatly appriciated
thanks heaps =).
Ice

ok, what hp, and how old? if it has points and condensor system, better to buy a kit to replace it all, then the coil, make sure the flywheel is clean of rust, and gap the coil there with a dollar bill, so its hard to pull out, but doesn't tear, then spin the flywheel for catching and rubbing. there also should be a wire (kill wire ) that connects to the magneto coil, take that off and try it.

Not sure of the hp, the cylinder capacity is about 100ml deep and about 100ml diameter... u can work it out lol. Horse power unknown sorry...

Should the engine work with that kill wire off? cuz that would mean the base point wasnt earthed all the time which in this state it is, and i cant understand. From the condensor terminal, there are 2 leaving it, one goes to the spark plug lead, via that magneto thing, and the other is the stop wire? which goes to the side of the head, but is then further extended with a new wire which extended right around the engine to the middle terminal of what use to be the key switch. These 2 wires are earthed by an uneccesarily complex terminal with a nut holding them down and then some funny thing i duno lol. but where should that stop wires extension wire be?
thanks heaps for the feedback it has helped
Thanks ^^
Ice

is this on a riding mower maybe? i do know that they had a wire with a fuse coming out at the starter, theres a wire from the magneto, should be easy to get to, and is held on by a clip, that kill wire grounds the mag, and shuts the spark off, it'll run without that wire ,but you'll have to pop the plug wire off, or if its a un-insulated end cap, just a bare metal clip that hooks on to the plug, you can take a screwdriver, and ground the head of the plug, to the engine head to kill the engine.

Ok this is all confusing me heres how it is.

From the stator/generator? (ring of magnets and coil under flywheel) there are 2 wires coming out, one is a black wire, and one is a red wire which used to have a black plastic thing i asume was the diode on the end of it. thats all from there

then from the magneto (the coil that holds the spark plug lead from it) there is a wire going to the base condensor point, and then another wire going from that, going to the side of the head (earthed) and then extended further off that is a blue wire going to no where at present.

The starter motor has a positive terminal on it and is earthed as negative, as it is bolted to the head.


So i have a red wire coming from the stator thing, with no diode where there was one before hand. I have a black wire coming from the stator thing. I have a blue wire coming from the side of the head, which is earthed there and further extended to the base condensor point. I have a positive terminal on the starter motor.
Can somebody please simply explain where these wires should join please =D? lol
Any help on this would be greatly appriciated.
Thanks to those who already have, big help :D.
Thanks
Ice

by head, what do you mean, engine block? or up around the spark plug? there should be one wire that simply comes from the mag, and grounds. so the wiring in it is pretty much everywhere? maybe someone else would know on the wiring, but what is it on?

can we just simplyfy this here.

The motor runs without a starter motor or a battery in the circuit so lets knock those out. Im still gona use the starter motor to turn the engine over but ill do it by touching a wire on it so itl be an independant component.

I know for a fact this engine runs without a battery or starter motor cuz we use to run it with just a pull cord.
So this means i can ignore the generator/stator under the fly wheel correct? meaning that red and black wire can be ignored
so now ive got a blue wire coming from the side of the engine block, which is bolted to it with plastic washers underneath it so it is not actually earthed im sorry that was my mistake. That is connected to a wire that runs up to the condensor base point, and then another wire runs off that base point to the magneto. From undernearth the magneto there are 2 fine wires uncoated and they are grounded and twisted together. And then i have the spark plug lead
so now all i have is the blue wire coming from the side of the head, (which is joint to the wire going to the condensor point and not earthed :)).

i know im repeating myself a bit but can u please tell me where this blue wire should be. And it is fine to cut the generator out of the circuit right?cuz the batteries not in it anymore.
Thanks heaps for ur feedback
lil bit more help would be greatly appriciated again :D:D.
Thanks
Ice

can't remeber entirely how the old ones were wired up, though was this a a givaway to you? may be a hack in the wiring. so it starts and runs? and that wire is dangling doing nothing and you can kill it? if thats the case, i'd ignore it.