Question on 1986 mercury outboard

[Alexthor811]

Will a 1986 80 hp mercury outboard lower unit bolt onto 1986 mercury outboard 90 hp

 

[jimmbo]

If both are 3 cylinder loopers, it should swap, if the 80 is a 4 cylinder, I don't think it will

 

[flyingscott]

Is the 90 a TOP 6? If the 80 hp is a 4 they might interchange physically but the gear ratios might be different. Someone will be along who knows way more than me.

 

[jimmbo]

An 86 90 hp would be an inline 6, the 3 cylinder appeared in 87

There was no 80 hp in 86. the last 4 cylinder 80 was 1983, the 3 cylinder 80 appeared in 87

That is why Model #s are very important

An inline 6 90 hp had a 2:1 ratio, the 4 cylinder 80hp had a 2.3:1 ration. The 3 cylinder loopers also had a 2.3: ratio, but the gearcase might be like the one used on the 4 cylinder loopers, different from the ones used on the older inlines