No spark Evinrude 100hp 1971 100193A

HI guys, need a spot of help ive been given an old 1971 Evinrude 100hp outboard she has been running great but 2 days ago she didnt start straight away as normal, it took about 10 seconds of cranking then she fired up with a slight backfire and was fine all day. The following day she wouldnt start at all. When i pulled out the spark plugs and checked for a spark there was none. After Further investigation i found the motorolla box at rear of engine (amplifier box) wires were crumbling<br />so i replaced the wires but still no spark.<br />How do i test the coil, points or amplifier?<br />Ive been told by and old guy in the Northern Territory that its possible to get rid of the amplifier and but in a car coil with a balast resistor and change plugs, i dont know if that is true or not so im calling on you guys to shed some light.<br />Thanks in advance<br />Chris Jeffrey (Australia)