Puch maxi S wiring issue/bad coil? Unsure

Johnathan Widen /

Hey I'm really aweful with wiring, attached is the diagram of my bikes wiring (The top one) I have no spark. The stator cover is up halfway with rust so it had some water in it. I cleaned the points and the ends of the coils and the magneto plates.

I want to bypass the switch and everything (lights,horn,killswitch) so that I can narrow it down to a bad coil how would I go about doing that? Thanks in advance


Re: Puch maxi S wiring issue/bad coil? Unsure

Blaine- The artist formerly known as Plumber Crack "(OFMC)" /

Starting on page 113 of the service manual best describes a step by step troubleshooting process for a no start/no spark and how to do exactly what you’re asking.

You may need an ohmmeter, cheap one is fine.

Re: Puch maxi S wiring issue/bad coil? Unsure

Re: Puch maxi S wiring issue/bad coil? Unsure

Chris Molden /

Does it have an internal coil, like shown on the top diagram? If so I believe the other wires can just be left disconnected.

On the internal coil type (coil inside the engine case behind the flywheel) there is no connection between the ignition and accessory circuits.

Just make sure the black wire isn't touching anything as grounding that is your engine kill switch.

At least that's how it is on mine...

Re: Puch maxi S wiring issue/bad coil? Unsure

Johnathan Widen /

Yes it's an internal coil. So the black wire is connected to the wire connector with nothing on the other side. So I should get spark if my coil is good? The yellow, red/green(I think) don't need anything?

Re: Puch maxi S wiring issue/bad coil? Unsure

Chris Molden /

Yeah, the three thin wires can just be left disconnected. The black will kill the spark/engine if its grounded to the frame/case etc.

The other two just go to the lights/horn. On some model/year variations one goes to the tail and the other to the head light, but other times the two power wires are just joined together before heading off to power lights and horn (like in the diagram you posted).

The black ignition coil is grounded to the case by the mounting bolts - needs to be clean and rust free on all contract points between the case the the metal on the coil.

Then make sure your spark plug lead is good - it screws into both the coil and the plug cap. Unscrew and chop off 10-20mm from either end and refit. Check continuity if you can, or just buy a foot or so of new lead for cheap peace of mind.

Are the points clean and actually opening/closing?

If all that doesn't work then it's probably the condenser (tin can looking thing) or the coil itself thats failed. Try replacing the condenser first - cheapest of the two.

Also are you sure it's not sparking? Sounds dumb, but I was sure I had no spark - couldn't see a thing resting the plug against the case. Then I turned it over with the plug lead disconnected and got a zap to my leg!

Hope I don't sound patronising, I'm no moped expert, but I spent a while trying to figure this stuff out for myself - all the US mopeds seem to have external coils, so the info in the wiki etc is a little confusing at first.


Re: Puch maxi S wiring issue/bad coil? Unsure

I would measure the coil for resistance. You said it looks like it spent some time wet, water can destroy the enamel insulation between the windings, causing a short an killing the coil.

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