Power head exchange ?

[Gulf Boater]

Hello all does anyone know if a power head from a 89 125 Force will fit in my 94 120 force body ? I need to rebuild mine 2 cylinders down to 30psi and have found a nice 125 powerhead and was wondering if that would be a direct fit into my housing.

 

[bentle]

Re: Power head exchange ?

the power head will fit ok in housing.
The power strip on the 89 is different than the one on the 94 so you may need to change the butt end connectors on your wires to fit the 89power strip..
Also the crank shaft splines that the drive shaft fits into on the 125 is 15 splined.
The 120 is 13 splined so you may need to find the right drive shaft.
If you can get the whole outboard then do that cause the 125 lower leg (edit) may be longer than the 120.

 

[Gulf Boater]

Re: Power head exchange ?

Thanks again for your help bentle. I ended up picking up a nice Force 125 today for $400 with a boat and trailer te boats junk but the trailer is in decent condition so couldn't pass it up. My other motor I now plan to pull apart and see wat the cause of low compression is. Seeing the Vid SWICK posted has inspired me to jump into it. If not to bad I may rebuild while using my new motor. Are allot of the parts interchangeable between the 2 motors as far a carbs and reeds etc . Also what year did they switch from the 125 to th 120 ?

 

[jerryjerry05]

Re: Power head exchange ?

They switched in 1990 I think.It was only a number change.No real difference.
After 91-92 they started using Mercury parts.Lower unit/electronics etc.
2 cylinders with low compression,next to each other usually means a bad head gasket.Remove the head and check before you do a big dismantle.
(If you can get the whole outboard then do that cause the 125 lower leg is longer than the 120)???
They make 2 sizes a 20" and 25"

 

[bentle]

Re: Power head exchange ?

Jerry is right there is two lower leg sizes as he stated.
What I meant to say was the 125 lower leg may be longer than the 120.

Heck yeah if that 125 force you purchased runs well then use it and rebuild the other for a back motor.
I toasted my lower gear case on my 1994 120 force on my last trip at lake powell and thought I was going to be without.
Well turns out that my 1989 125force lower gear casecase fits the 120, just had to use the drive shaft from the 120 because its 13the splined. Gear ratio is a bit different and will may cost me a couple numbers on my tack but I can live with that.