9.8 intermittent spark

[rainycity1]

I have a 1975 Merc 110 9.8 HP. One cylinder fires intermittently or not at all at low speed but seems to fire at high speed. I have heard of coils breaking down under a load but not vice versa. Any ideas? This is the breakerless ingnition system. I have a spark tester so I can actually see the spark when it fires.

 

[andy6374]

Re: 9.8 intermittent spark

Stator?

 

[rainycity1]

Re: 9.8 intermittent spark

Stator?

I found a chart with the ohm readings for all the ignition components. One of the two ignition coils has an open circuit between the ground wire and the tower. I will replace the coil and post the results.