pioneerman
ArboristSite Operative
The P39s used two different coils. Early models used the blue coil that is shown in your picture. They are the same coil as the farmsaw models and the small P28s. The later model P39s used the black Phelon coil which is the same as the P52, P42, P45, P62, P65. They are not interchangeable because the flywheels are different, and I'm not sure the mounting holes on the cylinder are the same.