1991 Force 150 hp

[Drfishing]

I have a 1991 Force 150 hp. Lower end is deteriorating and seal is visible through casing.
I know lower end units will fit from 1989-1994 85hp-150hp. Hard to find reasonable.
Q. Are any mercury lower end units compatible ?

 

[Drfishing]

Lower end seal exposed

 

[Nordin]

No there are no Mercury LU that will fit.
1 piece LU from Chrysler 3 and 4 cylinder and Force 3 and 4 cylinder will fit.
As your 150Hp is a 1991 year model the LU has the 2 piece drive shaft but a LU with 1 piece drive shaft should fit too.

 

[Drfishing]

No there are no Mercury LU that will fit.
1 piece LU from Chrysler 3 and 4 cylinder and Force 3 and 4 cylinder will fit.
As your 150Hp is a 1991 year model the LU has the 2 piece drive shaft but a LU with 1 piece drive shaft should fit too.

@Nordin is there any specific years I can look for? Or is it the same as 89-94? Thanks in advance

 

[Nordin]

The 150Hp was manufactured from 1989 until 1994 and they had the 2 piece drive shaft.
I am not 100% sure but in 1989 the 85Hp and the 125Hp had the 1 piece drive shaft.
Pre 1989 they (85 and 125Hp) had 1 piece drive shaft.
In 1990 the 85Hp was replaced by the 90Hp and the 125Hp by the 120Hp and all had the 2 piece drive shaft.
If you want the 2 piece shaft you have to look for 1990 or newer LU (up until 1994).
If you can manage a 1 piece shaft LU you can look for late 1970:es 3 and 4 cylinder Chrysler and from 1984-85 and later 3 and 4 cylinder Force.

 

[Jiggz]

Another thing to consider when replacing LU is the existing gear ratio. Your '91-150HP uses 1.93:1 ratio. The 84-89 125's uses the 1.73:1 ratio while the new 1989-125HP uses the same 1.93:1 ratio. The 85's uses the 2.01:1 ratio.

 

[jerryjerry05]

From 1992/3 they used the same gear ratio on all the bigger motors 90/120/150