Merc 9.9 cranks but won't start

Help please. 17 ft fisher with 2000 merc 9.9 remote steer and elect start. Upper unit brand new last summer. Last time out had battery issues. Replaced starter battery and deep cycle with one AGM. connected pos and neg's for engine, trolling motor and dashboard electronics (3 pos and 3 neg total). Turned my back for a minute and when I looked back, smoke from under dashboard. Analysis revealed a serverely burned black wire from ignition to fuse panel and blown 5amp fuse. So I assume I must have crossed wires when attaching to new battery. Replaced the fried black wire and fuse. Checked all other fuses on panel and all OK. Everything electronic appears to be working including trolling motor, nav lights, live well, bilge, horn, all gauges and both fish finders. Problem is engine cranks but doesnt turn over. Kill switch is in Run position. I went back underneath dash and replaced 2 other wires that looked like they might be affected, although I think it was melted wire cover from the fried one. Still wont start. Are there fused on the engine that may have blown? All connections on engine clean and tight as engine is new. Need help.Thanks for your support. Dan

Re: Merc 9.9 cranks but won't start

Additional information >>> Purchased spark plug tester and I'm not getting a spark to either cylinder. Removed plugs and they were wet so I assume gas is getting pumped. If anyone can offer expertise on where I need to go next to fix, I would be very appreciative. Again, all gauges work as does trolling motor. Kill swicth in RUN and I looked behind throttle and all wires look clean and in good shape. I also checked all fuses and they seem intact. 20amp in motor ok as well. All wires to engine clean and tight as head was replaced last summer and less then 5 hrs total on new head.