No ignition sound after a spark at the alternator.

[Dunnjiman]

2007 Bryant
5.7 mercruiser MPI

I realised my batteries were draining over a weekend and looked and saw my alternator cable had fallen off. I reattached it but somehow there was quite a spark and now when I turn the key, no ignition beep or depth finder in dash. Blower, bilge, horn all work. I checked every fuse I could find over a period of about 2 hours, fuse cluster on top of the engine, main 50 amp breaker on top of motor, fuses behind instrument panel, and about 5 stragglers. Boat is in neutral, safety tether is correct. I was hoping someone had an obvious answer.

 

[Fun Times]

Probable the 90 amp fuse on the starter has blown. Item number 8, http://www.mercruiserparts.com/bam/s...31754/15322/10

Check for 12v power at the orange power wire on the backside of the Alternator. If no power there, then there's a good chance the fuse is blown if everything else is in normal working order.
This image of a bad fuse below should help give you a better idea of the starter fuse image and location,