Advise on engine electrics PLEASE

[finnrib]

Hi All,
While recently replacing battery box and battery (2007 Zodiac Pro Open 5.5) I very briefly connected positive to neg and vice verca. Now, engine (2007 Yamaha 100hp) would'nt start or trim and Yamaha guages d'ont display any info. Boat electrics fine. When I connected ignition to bilge electrics engine started but eventualy blew fuse. Can any one tell me what has gone wrong ? All fuses are ok. Any ideas on this problem would be greatly appreciated.
Regards, Finnrib.

[Pikey Dave]

When you say "won't start" is the starter turning & engine not firing, or is the whole thing dead? If it's all dead, i'd make sure that you have checked all the fuses, is there one hidden away on the engine block somewhere?

[Chris]

There will probably be a blade fuse under the cover of the engine that has blown. Hopefully thats all

[jambo]

Yep I would certainly carefully check your manual for all your engine fuses.

[Damien.]

I'll be honest, I haven't had much to do with Yam's.

That said and applying Merc/Mariner logic, there should be fuses located on the engine with the sole purpose of protecting electronics when cases like this should arise. Check these carefully and depending on your boat set-up, there could be a breaker board or main fuse located nearer your battery or isolation switch.

Best of luck.