I have 600 ford tractor either 55-56 I think? The last couple of years the points would be burned out. I replaced it with an electronic ignition last year and it ran fine. This year it wouldn't start. I put fuel addivite and new fuel in the tank it wouldn't start. I check the key to the coil with a test light it was good. I check the coil from the distributor with the test light and it was good. I check the pugs with a spark plug analyzer and the spark was white. I read online that the spark should be blue and replace the coil, it still was still white with the spark pug analyzer. I have had drain the fuel in the tank and put in new fuel, no start. I have cleaned out the sediment bowl and put the new filter, no start. I have turned the screw under the carburetor and gas was come out. I have put my hand over the air input of the carburetor and it has suction. I have put starting fuld in the carburetor still will not start. Does anyone have any suggestions?