Coil boil

[Merc Cruzer]

Anyone see a coil boil. Just got back from a test drive after adjsuting the brakes and noticed the coil had bubbles. It is hot outside today.....6 volt system and just checked the voltage and it is charging at 6.5 volts.

[BUBBAS IGNITION]

Pretty common if not using a dropping resistor before the coil.
The coil is oil filled and typical running voltage is more like 4.5 volts with a dropping resistor before the actual coil.
Usually the coil is vacuum packed with oil and allows for expansion when hot. However the coil is sealed and a leak means breakdown of the seals.

Using two ressitances lowers the wattage to each and lowers the heat....you are lucky it ran you home.....
Had it been one of the newer off shore units it would have died ...

[Merc Cruzer]

Bubbas:

It has run for over 20 years and just now failed. Picked up a new BW coil, will look for a NOS.

[BUBBAS IGNITION]

Originally Posted by Merc Cruzer

Bubbas:

It has run for over 20 years and just now failed. Picked up a new BW coil, will look for a NOS.

Could be it just now had seal fail.
My bet is on a change in primary resistance causing the heat build up.
Running voltage should be less than battery voltage...

[ken ct]

It also looks like its sitting right on top of the exhaust manifold. I would move it elsewhere. ken ct.

[Merc Cruzer]

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Ken:

Factory bracket and factory location as far as I can tell. I did pull the new coil up a bit so the bracket is half way up the coil.

Bubba:

The new one in on shore - Mexico