You have a bad battery. Itís not sustaining a charge under load and that is required for ignition and starting. 6.4 V static is not a full charge; itís only about 85% and that is while being charged. You need to check static.. As stated a fully charged 6V battery should read about 7.5V static. Take the battery to your local starter/alternator shop or auto parts store and they can bench test on the proper equipment under load. It takes a minute and is usually free of charge Ė pun intended. Is it a front mount or an angle mount distributor? A 9N/2N or an 8N? Only matters if your whole system is as OEM -6V/POS GRN and wired correctly. That means a 1 Wire/3 Brush generator and cutout if a 9N/2N after s/n 12500, and a 3 wire/3-Brush generator with a Voltage Regulator for early 8Nís, 2 Brush/3-Wire for late 8Nís. BTW, the 9N/2N uses a 1-wire starter motor with NO solenoid and the 8N uses a 3-wire starter motor with a solenoid. All things being equal, a correctly tuned distributor is vital to ignition/running. Everything must be wired correctly as well. Start with testing the battery. If bad, replace with a new GRP 1 6V AG type and donít get a bargain house model. Invest in a good brand like INTERSTATE, DEKA, EXIDE, or DURECELL. The other item well worth the in investment is a float charger, not a trickle charger. The Battery Tender brand is a good one. Simply charging a battery does not ensure you have a good battery. A float charger will maintain a full charge in the battery when connected at idle times so itís ready to go when needed. It will also prolong the life of the battery. The biggest reason battery life is reduced is the constant discharging and recharging. If you want at least 6 years or more on your battery, get a good battery and a float charger. Start there then go thru the wiring and components.
Tim *PloughNman* Daley(MI)