1989 Force 150 Can lower end from a 91 be used?

[MikeyArriva]

Hey folks, I am trying to replace the lower end of my 1989 Force 150. The only one i can find at the moment is a 1991 full engine with blown crankshaft. the pic of the lower end looks pretty much the same with a few differences. such as my water intake is right behind the prop and this one sits up a bit higher. but for the most part everything looks really simmilar. does anyone know if they could be used together? I know the manuals i've seen online show 150's from 89 to 92 so i assume most things are interchangeable but I don't know enough about it and don't want to make the 5 hour drive to find out it won't fit. Any help would be greatly appriciated thank you!

Mike

 

[Frank Acampora]

Re: 1989 Force 150 Can lower end from a 91 be used?

Yes, you can swap them--If the shaft length is the same. Some were 20 inch and some were 25 inch. If both have a two piece drive shaft, then you can swap in the correct driveshaft for your engine.

If you do buy it, from your description it is a dual exhaust lower unit and you MUST use an open hub prop as in addition to the exhaust snout, exhaust also passes through the prop hub.

 

[MikeyArriva]

Re: 1989 Force 150 Can lower end from a 91 be used?

Thank you. Is the 25 the 2 piece? Mine is just 1 but not sure length can mine be used?. How do I know if its duel exhaust. And actually I'm pretty sure the only aftermarket prop I could find last summer was open hub for duel exhaust so should be ok I hope. But if my engine didn't have duel exhaust before. How will it make a difference? Sry I'm really trying to learn

 

[Frank Acampora]

Re: 1989 Force 150 Can lower end from a 91 be used?



The black lower is a dual exhaust and the white is a single exhaust. The white does have four vent holes that I drilled just above the cavitation plate.

Supposedly--the dual exhaust allowed the engine to make more power.

Dual exhaust lower units have the water intake on either side of the leg, placed vertically (like a Merc) Single exhaust lower units have slots on the side of the torpedo.

25 inch is not necessarily a two piece drive shaft. I have a 1978 Chrysler 140 with a 25 inch one piece drive shaft. You really can not swap drive shafts easily. They must be shimmed.

You can use any lower unit from a 90 up to a 120, from 1978 up to 1991 (as long as the drive shaft length is the same). Some do have different gear ratios so you might need to change the prop. I don't know the ratio on your 150 so I can not tell you which other lower units would be the same.