Max I own an RL 24 also. I found that the Johnson 9.9 Sailmaster is a very reliable motor. IT has plenty of power to get you out of some very tigh spots.this motor is pushing 18 years old an still starts on the first or second pull.This is also a 2 stroke motor.
I had the same problem. I bought a 5hp Mariner with a long shaft (20") and am thrilled with the improved performance especially backing or slowing forward motion. The problem is, the motor is too high and I am not able to use the hatch cover, which I thought added a nice look. If I were going to do it again I would probably buy an Evinrude 4hp which I think to be plenty of motor (at least for Lake Perry where I sail) and would be small enough to fit nicely in the hatch and add the hatch cover. Either way, I like the 20" much better than the 15" shaft. It backs and slow forward motion much better and gives much more control. I wanted a 5hp 4cycle, but was unable to get one in the required time, so I opted for the 2cycle. I wish I would have gotten the 4cycle but 2 cycles, as you know, last forever if you take care of them and mix the fuel properly.
When i bought my rl 24 it came with a mariner 8hp sailmate that has an extra long shaft . In shallow water it is the first thing to hit bottom dragging it to an awkward position in the well and thus rendering it useless, i'm thinking of trading it in. Does this happen with a 20" shaft?