|
A few possibilities/solutions: The insides of the magneto must be scrupulously clean. Any dust, etc. under the coil cap, on the outside of the coil winding and the inside the distributor cap can cause it to short out when it’s damp. Also the coil cover must be gasketed against dust & moisture. If the cover gasket is cracked/broken replace it with a new one! Either the coil cover or dist cap has a hairline crack. If so the cracked part should be replaced. Make sure the spark plugs are clean and properly gapped. Dirty plugs and spark gap exceeding specification are difficult for a magneto to fire. A magneto-equipped tractor must have solid copper plug wires, and the plug wire insulation must be in good shape. RFI suppression or “resistor” plug wires just don’t work well with magnetos – especially under damp conditions. Finally if your H sits outside, a “boot” cut from a plastic antifreeze jug, an old inner tube, or similar. Then stick the boot over the mag to shield it from rain, etc. whenever your tractor is parked.
| 
