Re: Would Chrysler 12.9 hp LU fit on Force 15 hp ?
Perhaps it would. The same lower unit was used on the Chrysler 9.9, 10, 12.9, and 15. I am not familiar with the Force 15, but if Merc did not change it, it probably will fit.
First check the pattern of the bolts holding it to the midleg. If they are different, it will be enough to easily see; no slight differences. Then pull out the 15 lower unit. If the drive shaft is the same diameter and splines, you are probably gold.