Force 90: Lower Unit Interchangeability

[Bigprairie1]

Anyone know what other years and sizes of lower units will fit a 1991 Force 90HP?
I recently got a spare Force 90 with a cracked lower unit (winter freeze-up breakage). I am going to keep an eye out for an interchangeable, re-useable lower unit and perhaps rebuild it over the next few months.
Up until that point (and poor storage process) the motor/etc had been running great.
It was a good deal and came with a tilt/trim, etc.
Regardless, if anyone knows what will fit this motor I would appreciate the feedback.
Thanks!!

 

[Frank Acampora]

Re: Force 90: Lower Unit Interchangeability

Not sure exactly when Merc changed the bolt pattern however, Any one piece lower unit from white Chrysler (I think it was started in 82) through Force 1989 --75 through 140 hp. will fit up to the 1990 model year. If your engine has the same bolt pattern, you can use all these lower units. They only changed the skeg shape. Everything else about the case itself is identical. Only other difference is gear ratio. Force 85 and 90 are 2 to 1 Chrysler all except 90 were 1.78 to 1, and Force 120 and 125 were 1.78 to one.

 

[Bigprairie1]

Re: Force 90: Lower Unit Interchangeability

Thanks Frank,
Good info as usual...I have to think on it and make sure just what I have before I attempt to buy anything.
With any luck I'd find another lower unit and rebuild the bottom end over the winter and maybe have a spare motor....who knows.
Many Thanks!!!!