In Reply to: Re: 8n spark posted by Mike lavigne on January 06, 2020 at 18:41:18:
We have an excellent wiring diagram with all the ways to wire these N's whether 6V/POS GRN or as a 12V switch over job in our HOW-TO's forum - see LINK below. Download it and print a hard copy for yourself as a guide. I suspect you have a wiring issue. Using the pictogram, confirm your wiring meets the criteria shown for your front mount 8N 12V Conversion, no shortcuts. You say you have 26 years with your 8N so we will assume you know how to properly set the front mount timing and install the unit with the offset tang. Misalignment of the cam/tangs will bust the housing base, but you knew that already. Points are set to .015" and must be timed correctly as well. Next, verify you have a good battery, don't guess, have it tested on the machine at a starter shop or auto parts store. It doesn't matter if the battery is 6 months or 6 minutes old, if it won't sustain a full charge under load, it fails. Batteries can be bad out of door at the store. The cheaper off-brand units are prone to be most susceptible to poor life spans as well. Start with a good power plant -the battery; it's the heart of any electrical system. Battery cables are important as well. You need 12V style cables -like on your car -and toss the heavier 6V cables. Then before applying power, verify that wiring is correct. A 12V setup on a FM uses the OEM Ballast Resistor. Do you have one? Is the VR removed from the circuit? Is the coil 6V or 12V? If 6V you need to add an in-line ceramic 1-OHM resistor in the circuit (not shown in pictograms) but is not used if you have a 12V coil. Once the Ford front mount distributor is tuned-up correctly and tested, install and then can proceed with the spark test. See if these suggestions help at all. Incorrect wiring is the bulk of all non-starting issues whether 6V/POS GRN or 12V/NEG GRN. Start with these suggestions. Brice(VA) has a list of "75 Tips For N Owners" you can also download and use in your shop. Bruce and Farmer Dan (email@example.com) also have a detailed explanations on how to tune-up and time the front mount distributor. See if these suggestions help you.