ignition system problems
 

i own 1988 bayliner capri 1950. i have had it since new and pretty much
has been trouble free most of the time. within the last year i have
seemed to develop this ignition problem where as i seem to lose spark
to the plugs but have 12 volts at the positive term of the coil. its
very frustrating and made the boat very unrelible not to mention hefty
tow bill to get off the lake. it has a 3.0 litre gm 4cylinder with a
omc cobra. when i change the coil it seems to help but sometimes will
start to act up almost immediaetly. if any one has had a similar
situation please shed some light.