Help finding a lower unit for '89 Force 125

[ambrowns]

Hi, I am new here and after the third time out on my '89 bayliner capri since we got it, my skeg broke off of my '89 force 125 exposing the gears. It seems I need a new lower unit. I am a bit confused, however, about which years and models of lower units will fit my '89 force 125. I have found good deals on both a '90 force 125 lower unit and an '85 force 85 lower unit. It seems that the 85hp one has a 2:1 gear ratio as compared to the 1.73:1 on my 125hp(not sure how big of a difference that would make. If anyone has any ideas about which model will fit mine, please let me know.

 

[pnwboat]

Re: Help finding a lower unit for '89 Force 125

There were several variations used in 1990, so I can't say for sure if the 1990 lower end will work. It should, but I can't say for certain. The 1985 will work, however, the difference in ratio means that you may have to change props since the propeller will be turning less with each revolution of the motor.

 

[ambrowns]

Re: Help finding a lower unit for '89 Force 125

There would be no problem with changing props because when the skeg broke off, it bent my old one pretty badly and I will need to get a new one anyway. Any suggestions on a new prop with the new gear ratio? Also, would it be bad on the motor over a period of time to use the 85hp with the different ratio?

 

[Frank Acampora]

Re: Help finding a lower unit for '89 Force 125

The 2 to 1 ratio lower unit is more desirable as it will increase the top speed. Increase the pitch of your prop by 2 inches. for example: If you are using a 13 X 17 pitch prop now, go to a 13 X 19 pitch

 

[jerryjerry05]

Re: Help finding a lower unit for '89 Force 125

Make sure the shaft length is the same.They come in(I think 3 lengths)15/20/25.J

 

[ambrowns]

Re: Help finding a lower unit for '89 Force 125

How can I tell what length shaft I need? I know the '85 has a 25" shaft. Is there an easy way to tell what length it is?

 

[Frank Acampora]

Re: Help finding a lower unit for '89 Force 125

Measure your engine from mounting clamps to cavitation plate. It will either be about 20 or about 25 inches.

If your 89 is only a 20 inch engine and has a one piece drive shaft, it (the drive shaft) can be swapped into the 85 lower unit. (unless you would rather find another lower.)

 

[ambrowns]

Re: Help finding a lower unit for '89 Force 125

So, I now need to find out if mine is a 2 piece drive shaft? Are there certain years that 2 piece drive shafts were on them or is there a way to find out which mine has?

 

[jerryjerry05]

Re: Help finding a lower unit for '89 Force 125

Take it off and measure it at the base of the pump to top of the shaft.
Yours is a 1 piece.
You can measure the center of the transom to the bottom of the boat under the drain plug. It will be close to 20 or 25.If you have a cuddy it's probably 25,I installed a couple hundred of these on Bayliners.J