I have a 78 Evinrude 2 cyl 55 hp motor. When I put it in th he water it went backwards. The guy I got it from said it has s bv 70jp lower unit on it. Then I was told by others it had as 73-76 lower unit that would "fit" but the gears were opposite up I'd reverse and down is forward. What YEARS and HP and 2 OR 3 CYLINDER will fit and run the correct direction .Someone who knows more than me please help.

