Mercruiser 5.7 won't start

Question

My boat was running great, cruising about 3500 rpm when it suddenly died. No sputtering, just shut off. Got it restarted and after going a little further died again. Started the next morning, ran about 5 minutes then died. Now it will not start. turns over fine, got gas at accelerator pump, just no spark. took off plug wire from coil at distributor, held about 1\2 inch from ground, no spark. have voltage at coil, 10.5 volts, and 9.7 coming out of ignition module. are these voltages ok. tried new distributor sensor, no help. next is coil or ignition module. any ideas or suggestion. merc 5.7 thunderbolt V 1996

Answer 1

did you resolve this problem?  It had a very similar situation where my boat died after running strong at about 3200 rpm.  I could not get it restarted so I got towed in.  I tried starting it several hours later on the trailer and it ran great.  I let it run for about 10 minutes...no problems.  I would like to conclusively diagnose the problem to avoid getting stuck on the water.  I am wandering if the ignition module could have overheated, or if the ignition sensor could have an intermitten failure.