Coil overheating?

[porkchop85]

Good morning I have a 1983 SeaOX 230c with the 470. I hope to make this as readable as possible. The engine has a new cap, rotor, plugs, plug wires, points replaced with pertronix2 though on the water I installed a pertronix 1(see below) (stator replaced with alternator) 4 inch exchanger, new elbow, new carb, electric fuel pump.

Yesterday after about 30 minutes of running the engine sputtered and shut off. Boat did this last year so I replaced the 3 ohm flamethrower with 1.5 flamethrower. Same symptoms sputters and shut off. On the water replaced pertronix 2 with a pertonix 1 as I carried it as a spare. Wouldnt start with ether to rule out fuel. Boat will start and run fantastic once it cools off.

Am I over heating my coil? It has direct 12v with no resistor wire per the instructions. I was reading 14.5 volts with no electrical load and 13.8 volts with an electrical load(bilge fan). Should I ballast the coil so that it does not get the full 14 volts from the alternator?

 

[Bt Doctur]

I would, cant hurt

 

[porkchop85]

Ok I will try that

 

[gm280]

Running the 3 ohm setup would draw about 4.7 amps. Changing to the 1.5 ohm will draw 9.6 amps at 14 volts each. Is the coils heatsinked with a good aluminum heatsink? If you suspect heat being the problem, measure the coil cold and when it gets hot and see what the resistances are on both the primary and secondary sides. That will give you a better idea of if heat is causing it or not. If the coil reads the same either way, or close, then it isn't the coil being the issue... JMHO

 

[porkchop85]

Makes sense! I am just assuming because I had a spark plug tester on board and had no spark until it got cold.

 

[porkchop85]

So I put a ballast resistor inline with the coil and fed the pertronix separately with 12 volts. Coil was getting 8 volts. Engine started perfectly and ran for about 30 minutes and shut down again. I still had power to the coil but no spark from the spark plug tester. I also ohmed out the coil amd it has over 400 ohms.

Why am I cooking coils?