Ignition Question

It could be the coil. Put an ohmmeter across the two coil terminals and see if it reads around 3 ohms. The odds are greater that it's the electronic ignition.

Try pull starting your D17 before starting to chase down the cause. Recently fixed the neighbors D14 W/ Petronix and Flamethrower (I installed it and sold him the tractor several years ago). It has started and ran great all these years for him. Then all of a sudden, and with no prior symptoms, would not start with the starter; started right up and runs great with a short pull. Did a voltage test to the coil; 12.5V w/o starter. 8V with starter. Re-installed the points/condenser and now starts and runs great. I told him the starter was dragging too much and lowering the voltage to the ignition. The Petronix ignition is more sensitive to voltage changes than points. Told him that pulling the starter and working on it was in his future, could be as simple as cleaning the groves and/or emorying the commutator and/or replacinf the brushes. Once he cures the starter drag issue, he can reinstall the Petronix ignition.