Thinking more on this, raise the drive enough so you can see the engagement between the bell hsg shift lever and the lower gear hsg lever. Readjust so FWD engages. The lever should be dead ahead, forward, 12: o'clock. Neutral at 11; o'clock, REV: 10: o'clock. If you don't get this travel, your shift cables and mechanism probably have slop.
Next, pull the outdrive. Hold the O/D lever in FWD. It should move no farther right than dead ahead., With a prop on, rotate the prop CCW. It should lock solid, and ratchet CW, and you should feel the shift lever twitching. Move the lever to the left as far as it will go to the left, hold it and try locking the prop CW, ratcheting CCW. If good, your clutch is good. But If the lever goes much past 11 o'clock - 45 degrees, I'd suspect worn parts in the lower hsg shift yoke, splines, or shift spool. I think this would be rare since everything down there is submerged in lube.
Your controller should have enough throw to go much well past 45 degrees to hold force on the clutch in REV . You can check your controller's throw and slack by setting the cable adjustment back so the lever it's just a few degrees left of dead ahead with the controller in full FWD. (this important to insure the cable is preloaded a bit when the drive is back on) This will push the slack out. Be sure to have the lever's roller engaged in the shift cable slide slot. Hold some resistance on the bell hsg lever and have a helper shift to full rev. This will pull the slack out of the shift cables. There should be enough travel to push the outdrive lever well past it's 45 deg. REV engagement point.
It should add up that the cable's full travel should exceed the lever's travel. If not, either too much cable slack, or worn clutch shift parts in the hsg.
