Interchangeable powerheads?

[Saltheart Foamfollower]

Hi everybody, I'm trying to find out if a Force 120 hp outboard powerhead is interchangeable with a Force 120 hp L-drive powerhead of the same year range? Any help would be greatly appreciated.

 

[Frank Acampora]

Re: Interchangeable powerheads?

I believe the blocks use the same mounting stud pattern with a different match plate. They should be interchangeable. However: I have been told by a reputable source that the L drive crank is balanced differently--I don't know if the timing tower and linkage is the same though. If it looks the same, it most likely is. That's the best I can do for you.

 

[Saltheart Foamfollower]

Re: Interchangeable powerheads?

Thank you for the info Frank. Yesterday I picked up a good running 1993 120 hp outboard, with no lower unit, for $300. After pricing parts for the 1991 120 L-drive, I decided that even if the powerhead wasn't interchangeable, many of the parts are. Dollar-wise, I made out like a bandit this way. Out of curiosity, if the complete running 93 bolts right onto the L-drive, would the different crank balance even matter? I'm very mechanically inclined but boat motors are a new field for me and I'm learning as I go....lol.

 

[Frank Acampora]

Re: Interchangeable powerheads?

Never having done this type swap, I could not tell you about the balance and different crank.

However, before trying to mount the block, check the splines on the bottom of the crank and see if the L drive stub shaft will slide into them. There is also the possibility that my source meant the crankshaft splines are different. If different, then swap crankshafts. Once the blocks are demounted, it is relatively easy to swap them.

If you do the block or crank swap, post results so we all learn something more, based on fact, about the L drive.