'79 80 hp lower unit, compatible w/ '85 75 hp brown band ??

[roscoe]

I don't have any books showing compatibility of these 2 motors.

Friend has 1985 75 hp brown band Merc, with no lower unit.

He has found a lower from a 1979 80 hp. 4 cylinder.

Is this gonna bolt up for him?

Thanks in advance.

 

[Faztbullet]

Re: '79 80 hp lower unit, compatible w/ '85 75 hp brown band ??

All the 4 cylinder unit will interchange as long as they have the 2.3:1 gear ratio. I have seen posted that a 2.1 ratio will work by dropping prop size but I have seen that it(2.1) makes it lazy planing and hard to pull skiers.

 

[roscoe]

Re: '79 80 hp lower unit, compatible w/ '85 75 hp brown band ??

Ok, thanks much.