99 merc EFI lower unit same as '06 opti lower unit

[mcgyver]

Hey, have a compatabilty question. Lower unit on my '06 opti 150 went. Have located a '99 150 EFI lower unit that the owner says is the same...can anyone confirm?

 

[galamb]

Yes.

The 150 Opti and the 150 EFI did share a common lower unit. So provided you are swapping a long shaft for long shaft or XL for XL all should be fine...

(edit for important detail - compared the gear housings which are exactly the same - ditto 99% of the guts. What IS DIFFERENT - the 150 EFI utilized 2.0:1 gears, the 150 Opti has 1.87:1 regular, 2.0:1 for the high altitude models. This would necessitate a prop change to get similar results)

 

[faztbullet]

According to my chart they are the same ratio.....

[SIZE=-1]Mercury[/SIZE]	[SIZE=-1]2.5L/2.5L EFI[/SIZE]	[SIZE=-1]150/175[/SIZE]	[SIZE=-1]5000-5600[/SIZE]	[SIZE=-1]1.87/1[/SIZE]
[SIZE=-1]Mercury[/SIZE]	[SIZE=-1]('99) 2.5L[/SIZE]	[SIZE=-1]200[/SIZE]	[SIZE=-1]5000-5600[/SIZE]	[SIZE=-1]1.87/1[/SIZE]
[SIZE=-1]Mercury[/SIZE]	[SIZE=-1]2.5L EFI[/SIZE]	[SIZE=-1]200[/SIZE]	[SIZE=-1]5000-5800[/SIZE]	[SIZE=-1]1.87/1[/SIZE]
[SIZE=-1]Mercury[/SIZE]	[SIZE=-1]3.0L[/SIZE]	[SIZE=-1]225[/SIZE]	[SIZE=-1]5000-5500[/SIZE]	[SIZE=-1]1.75/1[/SIZE]
[SIZE=-1]Mercury[/SIZE]	[SIZE=-1]3.0L EFI[/SIZE]	[SIZE=-1]225[/SIZE]	[SIZE=-1]5000-5800[/SIZE]	[SIZE=-1]1.75/1[/SIZE]
[SIZE=-1]Mercury[/SIZE]	[SIZE=-1]XB 3.0L EFI[/SIZE]	[SIZE=-1]250[/SIZE]	[SIZE=-1]5800-6100 (6250)[/SIZE]	[SIZE=-1]1.75/1[/SIZE]
[SIZE=-1]Mercury[/SIZE]	[SIZE=-1]Optimax 2.5L[/SIZE]	[SIZE=-1]150[/SIZE]	[SIZE=-1]5000-5600[/SIZE]	[SIZE=-1]1.87/1[/SIZE]

 

[galamb]

Yes, I think you are correct. I popped open my service manual (2000 edition) and got the following chart -



Went back and had a look at the 1992-2000 manual and got this chart -



so sorry for the confusion, but definitely confirm it's a pre-2000 model for the donor...