Swapping out a 88 Force 125 with a 91 Force 120

[cleopatraiz]

Have a 88 Force 125 Model 1251X8A Ser 1849 on a Bayliner Capri 1900 open bow. Engine is done. Looking at a 91 Force Model 1208F91A Ser 021419 as a replacement. Getting conflicting info. Latter is 20" shaft, former 25. Can I take the 88 lower end and marry with the 91 using the spacers etc from the 88 to repower or any other ideas?

 

[racerone]

First thing is to measure the 2 motors.-------There is lots , lots of confusion on what / how to measure these motor.-----Many a short shaft has been called long in the past.

 

[cleopatraiz]

They are as stated, we're sure and measured. Thanks!

 

[Nordin]

What is done with the 125Hp?
If it is the power head that is done and the midleg and lower unit is okey then you can swap the power heads.
The 120Hp power head will fit right on the 125Hp leg, same bolt pattern and the drive shaft will fit in the 120Hp crank.

The major different between those is that the 120Hp has a lager bore 3,375 in and the 125Hp has 3,312 in.

 

[jerryjerry05]

There are NO spacers for the 91.
The mid section is where they make up the difference.
The place you mount the drive on the long is 5" longer than the short.
Like Nordin said, you can swap the powerhead to the old base.
Or you can cut the transom down 5"

 

[puffitu]

Should be an easy swap out IF you’re swapping out the power head only...I just did a similar thing on mine only in reverse; I went from 1990 120hp to 89 125hp. Kept the mid and lower on there. Although, later swapped out the transom holder and lower end as I noticed the existing lower was beginning to have some issues and a snapped hinge pin on transom.Just when you’re doing only the power head swap, pay close attention to spacer plate (if applicable on both motors)between midsection and power head. Even if your new doesn’t have then use the spacer from the old and it should be just fine. You will need a gasket though

 

[jerryjerry05]

They only make a 20" and a 25"
Confused? post a pic of the mid section.

 

[cleopatraiz]

Thanks for all the helpful info!! We're deciding what to do.