Re: '49 Dodge Flat Head No spark 12v

Posted by John T on June 20, 2021 at 04:38:42 from (45.16.200.171):

In Reply to: Re: '49 Dodge Flat Head No spark 12v posted by ErnieD on June 19, 2021 at 18:45:10:

Thanks for the feedback, you now post

1) Thank you all. I have no spark. Repeat no spark. Test light flashes on the coil on the distributor side. Points and condenser appear to be newer;

2) Will rig a jumper to bypass the ballast resistor to the starter motor

NOTE if its a full true 12 volt rated coil DO NOT USE a ballast as that will weaken the spark !!!!!!!!!!! A ballast is used ONLY if its a 6 volt coil on a 12 volt tractor

3) In case you missed it, heres my response yo your original post

If it was converted to 12 Volts, you can use EITHER an old 6 volt coil PLUS an external series voltage dropping (12 down to 6) Ballast Resistor. If its a full true a 12 volt coil, you don't use a ballast resistor or ballast by pass circuit when cranking..

If your test lamp on the coils output to distributor terminal is flashing ON (when points open) and fully OFF (when points closed) when cranking that tells me the points are operating opening and closing the coils current as they should.......

TRY THIS Remove the coil wire from the dist cap (leave coil end intact) and place its terminal within 1/8 inch or so from tractor iron turn her on and crank her over TO SEE IF THE COIL IS FIRING a spark to ground ?????????

If so, the coils working and there may be a problem in the dist cap or rotor ......... Ive seen many rotor tips short out to dist shaft and dist caps with a crack or carbon trace or full of moisture preventing spark at the plugs

If the coils NOT firing it could be bad

If the condensor is shorted out the coil wont fire

If the condensor is open or weak it can still fire but a weaker spark and the points will burn soon

Check easy things first like points and condensor and dist cap and rotor BEFORE the more expensive coil although sure if all else is okay that can be the problem

Check out my Troubleshooting Procedure when theres no spark, it can help find the problem

http://www.ytmag.com/cgi-bin/viewit.cgi?bd=farmall&th=5745

John T

• John T's Ignition Troubleshooting

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