Electrical Question: Arching between manifold air cleaner pipe

I'm guessing this is normal because the tractor runs great.

FYI, this arcing condition only exists when the tractor is running - so it is related to the firing of the plugs. I'll check the ground strap and take it from there....

Regards, Patrick

You doubt? Go out on a dark nite and watch the little blue sparkies dance on your old dried out sparkie insulation.

Gettcha a new set of old time "copper core" sparkie wires. DON'T GET modern anti-radiostatic carbon core sparkie wires..... ...Dell

If it is a 12 volt conversion, the battery - post should be ground, the coil - post should be connected to the points, the coil + post should be connected to the ignition switch/dropping resistor.

Hooking the coil up backwards gives a somewhat weaker spark, and might also result in the electrons finding a somewhat odd way to get back home.

For what its worth - and I know that David, Dell and Soundguy + others don't need the information, I found a couple of useful articles which go into a little more technical detail on ignition systems.

Link
914_ignition_troubleshoot/
914_ignition_troubleshoot.htm

Thanks again!

Cars are relatively safe in thunderstorms not because the "rubber" tires are insulated, but because the car and its tires form a grounded Faraday cage around the occupants.

Most rubber/plastic/vinyl products used in automotive service contain additives such as carbon black to enhance resistance to sunlight and chemicals. These additives make the material more conductive than the pure base substance would have been. The hoses for the intake tube would be good candidates for such additives, given their proximity to gasoline.

Assuming that you see the sparks only with the tractor running, and assuming that there are no bare 6 volt wires shorted to the intake pipe up under the hood, I suspect what is happening is the intake pipe is providing an alternate ground return for the spark plug voltage back through the air cleaner and the sheet metal of the hood and thence to the battery/coil. Perhaps your battery ground strap needs to be cleaned up, or one of your plug wires has an intermittant short to the block.

You can confirm the source of the sparks by shutting the engine off, then turning the key back on (but not starting the engine), and wiggling the intake pipe. If there are sparks now, the intake pipe is in contact with 6volts somewhere. If there are not, the sparks are related to firing the plugs.

Jim C

Assuming your tractor is still 6v pos grnd, the manifold is grounded to the block via the studs..atherefore it is positive That would mean that the air cleaner pipe must be touching a a negative wire somewhere.. Perhaps a wire to the resistor or out to the ignition has rubbed some insulation off and has a bare spot.

My other guess would be a leaky high voltage wire to a sparkplug.. or from coil.. depending on how they are routed.

If I've left something out, I'm sure someone will fill in where I've left out.

SouNdguy

Remember the 6 volt mantra: "keep'em clean, bright, and tight"..... ..Dell