mercury 50hp red band misfire

hello I have a problem with my mercury 50hp 3 cylinder outboard believed to be of 1989 origin (red band) the only identification numbers I can find on the unit are as follows serial number 9549343 on transom mount engine bracket.number on cylinder head reads 1025-8363, 69554/us,pat,3773010, address marine power Europe,division of Brunswick,sa, made in Belgium,vivieres 84822. bad misfire on startup,removed plugs to check,running only on 2 cylinders sometimes number 1 plug sooted up 2+3 dry sometimes 2+3 sooted up number 1 plug dry.tried adding 16 fluid ounces of sea foam to 1 imperial gallon of petrol had no effect just loads of smoke.cleaned out carburettors,changed plugs for new ones,changed plug leads and cnnections,replaced 3 new coils,new ignition switch box,new rectifier (the diamond shaped one) new inline fuel filter.replaced 60 amp/hr 12v battery with 2x inline 54 amp/hr batteries pos to pos ,neg to neg as use electric motor as back up and trolling when sea fishing.the units are mounted on a flatacraft force 4 rib.I would greatly appreciate any help you can give me.thanking you in advance. bill.

Replace the ignition coil(s) on the bad cylinder(s). And the wires as well.

Jeff

PS: ALL of those black rubber caps that go over the wire terminals on the coils and switch box MUST be in place or the terminals will sort together (300 + volts!)

It mentions he has 3 new coils and a new switchbox as well.----------What else can it be than?

If its a new to you motor check the firing order as someone may have been trying to repair before you got it. If you have had it a while and this just stared happening it could be a couple of things: 1) weak stator 2) trigger problem 3) carbs flooding intermittenly(float or inlet needle)

hi jeff,thanks for replying so quickly to my query on mercury 50hp outboard misfire.all those black rubber caps you mention the ones over the 10mm nuts I had problems getting them to fit properly so I will definitely check those out first thing tomorrow.i did fit new high tention leads to the plugs with new connections.did not check wires just fitted them back in place as changed the parts.i think you may have given me the answer to my problem.thank you I will let you know how I get on.all the best to you and yours .bill

hi thanks for your advise to my problem with mercury 50hp red band outboard.jeff thinks mite be the black connectors not fitted properly,it could be because I had trouble getting them to fit when I changed the coils and switch box,i've probably routed the wires differently.i did suspect stator trouble but was not to keen to lift the flywheel/starter mechanism.will have to if this is the case.you mention trigger problem,were do I look for it,i have sent off for a mercury mariner outboard manual on