90 HP Merc ... What's My Year and Model Please???

[bobbyg]

My 6 cylinder 90 HP Merc has a serial # 6086518. Can someome tell me the year (it was sold as a 1983 but I think it's an '82).

Also, is there a model number I should be aware of, too?

This is a 'Thunderbolt Ignition' system (lettering is on front cowling cover) ... is that a good/better/best ignition system?

Thanks