Re: L/U march
It should fit, however, the gear ratio may be different. The manual indicates that the 1988 125HP leg has a 1.73:1 gear ratio. The 1989 150HP leg has a 1.93:1 gear ratio. You probably should check and compare the actual legs before swapping. If this is the case, how will this affect your motor? The 1988 leg will put a little bit more load on the engine. Performance may suffer a bit. Worse case scenario, you may have to get a propeller with less pitch to re-gain performance. May lose a few MPH at top end.
A side note...I have a 1988 125HP motor with the 1.73:1 gear ratio leg. I swapped it with a 1988 85HP leg that has a 2:1 ratio leg. BIG difference in performance. I had to go from a 17 pitch prop to a 19 pitch prop just to get the RPM's down to 5600 at WOT. Motor was hitting 6000 RPM with the 17 pitch prop. Boat also picked up about 4 mph at top end when I put the 19 pitch prop on. Seems that these motors really like the gear ratio around 2:1.
